feat(extensions): show toast on load failure and export ChatbotView type

- Add `icon` field to `View` descriptor (static, set at registerView time)
- Track per-extension Disposables in ExtensionsLoader; add deactivateExtension()
- Subscribe ChatbotMount to registry changes so it reacts to activate/deactivate
- Add host-level unhandledrejection isolation to ExtensionsStartup
- Make extension loading non-blocking (host renders immediately, chatbot appears reactively)
- Document superset.chatbot location and chatbot registerView example in public API

superset-frontend/packages/superset-core/src/contributions/index.ts

@@ -17,23 +17,12 @@
  * under the License.
  */
 
-/**
- * @fileoverview Manifest schema for Superset extension contributions.
- *
- * This module defines the aggregate interfaces used by the extension.json
- * manifest and the `superset-extensions` build command. Individual metadata
- * types are defined in their respective namespace modules (commands, views,
- * menus, editors) and re-exported here for the manifest schema.
- */
-
-import { Command } from '../commands';
 import { View } from '../views';
+import type { ChatbotView } from '../views';
 import { Menu } from '../menus';
-import { Editor } from '../editors';
 
-/**
- * Valid locations within SQL Lab.
- */
+export type { ChatbotView };
+
 export type SqlLabLocation =
   | 'leftSidebar'
   | 'rightSidebar'
@@ -43,43 +32,14 @@ export type SqlLabLocation =
   | 'results'
   | 'queryHistory';
 
-/**
- * Nested structure for view contributions by scope and location.
- * @example
- * {
- *   sqllab: {
- *     panels: [{ id: "my-ext.panel", name: "My Panel" }],
- *     leftSidebar: [{ id: "my-ext.sidebar", name: "My Sidebar" }]
- *   }
- * }
- */
+/** Valid locations within the app shell (persist across all routes). */
+export type AppLocation = 'chatbot';
+
 export interface ViewContributions {
   sqllab?: Partial<Record<SqlLabLocation, View[]>>;
+  app?: Partial<Record<AppLocation, View[]>>;
 }
 
-/**
- * Nested structure for menu contributions by scope and location.
- * @example
- * {
- *   sqllab: {
- *     editor: { primary: [...], secondary: [...] }
- *   }
- * }
- */
 export interface MenuContributions {
   sqllab?: Partial<Record<SqlLabLocation, Menu>>;
 }
-
-/**
- * Aggregates all contributions (commands, menus, views, and editors) provided by an extension or module.
- */
-export interface Contributions {
-  /** List of commands. */
-  commands: Command[];
-  /** Nested mapping of menu contributions by scope and location. */
-  menus: MenuContributions;
-  /** Nested mapping of view contributions by scope and location. */
-  views: ViewContributions;
-  /** List of editors. */
-  editors?: Editor[];
-}

superset-frontend/packages/superset-core/src/views/index.ts

@@ -20,19 +20,12 @@
 /**
  * @fileoverview Views registration API for Superset extensions.
  *
- * This module provides functions for registering custom React views
- * at specific locations in the Superset UI. Views are registered as
- * module-level side effects at import time.
+ * Extensions register React views at named locations using `registerView`.
+ * Registrations happen as module-level side effects at import time.
  *
- * @example
- * ```typescript
- * import { views } from '@apache-superset/core';
- *
- * views.registerView(
- *   { id: 'my_ext.result_stats', name: 'Result Stats', location: 'sqllab.panels' },
- *   () => <ResultStatsPanel />,
- * );
- * ```
+ * Built-in locations:
+ *  - `sqllab.panels` / `sqllab.rightSidebar` / … — SQL Lab surface
+ *  - `superset.chatbot` — app-shell chatbot bubble (singleton; host renders one)
  */
 
 import { ReactElement } from 'react';
@@ -48,20 +41,23 @@ export interface View {
   name: string;
   /** Optional description of the view, for display in contribution manifests. */
   description?: string;
+  /**
+   * Optional icon identifier for the view, used in admin pickers and manifest
+   * listings. Static — set once at registerView() time.
+   * Dynamic icon states (e.g. notification badge) are the extension's concern.
+   */
+  icon?: string;
 }
 
 /**
  * Registers a custom view at a specific UI location.
  *
- * The view provider function is called when the UI renders the location,
- * and should return a React element to display.
- *
- * @param view The view descriptor (id and name).
- * @param location The location where this view should appear (e.g. "sqllab.panels").
+ * @param view The view descriptor (id, name, and optional icon/description).
+ * @param location The location where this view should appear.
  * @param provider A function that returns the React element to render.
  * @returns A Disposable that unregisters the view when disposed.
  *
- * @example
+ * @example SQL Lab panel
  * ```typescript
  * views.registerView(
  *   { id: 'my_ext.result_stats', name: 'Result Stats' },
@@ -69,6 +65,15 @@ export interface View {
  *   () => <ResultStatsPanel />,
  * );
  * ```
+ *
+ * @example Chatbot bubble (`superset.chatbot` — singleton, host renders one)
+ * ```typescript
+ * views.registerView(
+ *   { id: 'my_ext.chatbot', name: 'My Chatbot', icon: 'Bubble' },
+ *   'superset.chatbot',
+ *   () => <ChatbotApp />,
+ * );
+ * ```
  */
 export declare function registerView(
   view: View,
@@ -76,6 +81,21 @@ export declare function registerView(
   provider: () => ReactElement,
 ): Disposable;
 
+/**
+ * Narrowed descriptor for chatbot contributions (`superset.chatbot` location).
+ *
+ * Extension authors should use this type when calling `registerView` for the
+ * chatbot area. It is identical to {@link View} but makes the registration
+ * intent explicit and allows future narrowing (e.g. required `icon`).
+ *
+ * @example
+ * ```typescript
+ * const chatbot: ChatbotView = { id: 'my_ext.chatbot', name: 'My Chatbot', icon: 'Bubble' };
+ * views.registerView(chatbot, 'superset.chatbot', () => <ChatbotApp />);
+ * ```
+ */
+export type ChatbotView = View;
+
 /**
  * Retrieves all views registered at a specific location.
  *

superset-frontend/src/components/ChatbotMount/ChatbotMount.test.tsx

@@ -0,0 +1,91 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import React from 'react';
+import { render, screen } from 'spec/helpers/testing-library';
+import { views } from 'src/core';
+import { CHATBOT_LOCATION } from 'src/views/contributions';
+import ChatbotMount from '.';
+
+const disposables: Array<{ dispose: () => void }> = [];
+
+afterEach(() => {
+  disposables.forEach(d => d.dispose());
+  disposables.length = 0;
+});
+
+test('renders nothing when no chatbot extension is registered', () => {
+  render(<ChatbotMount />);
+
+  expect(screen.queryByTestId('chatbot-mount')).not.toBeInTheDocument();
+});
+
+test('renders the registered chatbot inside the fixed mount slot', () => {
+  const provider = () => React.createElement('div', null, 'My Chatbot Bubble');
+  disposables.push(
+    views.registerView(
+      { id: 'superset.chatbot', name: 'Superset Chatbot' },
+      CHATBOT_LOCATION,
+      provider,
+    ),
+  );
+
+  render(<ChatbotMount />);
+
+  expect(screen.getByTestId('chatbot-mount')).toBeInTheDocument();
+  expect(screen.getByText('My Chatbot Bubble')).toBeInTheDocument();
+});
+
+test('renders only the first-to-register chatbot when several are installed', () => {
+  const firstProvider = () => React.createElement('div', null, 'First Bubble');
+  const secondProvider = () =>
+    React.createElement('div', null, 'Second Bubble');
+  disposables.push(
+    views.registerView(
+      { id: 'first.chatbot', name: 'First Chatbot' },
+      CHATBOT_LOCATION,
+      firstProvider,
+    ),
+    views.registerView(
+      { id: 'second.chatbot', name: 'Second Chatbot' },
+      CHATBOT_LOCATION,
+      secondProvider,
+    ),
+  );
+
+  render(<ChatbotMount />);
+
+  expect(screen.getByText('First Bubble')).toBeInTheDocument();
+  expect(screen.queryByText('Second Bubble')).not.toBeInTheDocument();
+});
+
+test('isolates a failing chatbot so it does not crash the host', () => {
+  const FailingChatbot = () => {
+    throw new Error('chatbot blew up');
+  };
+  disposables.push(
+    views.registerView(
+      { id: 'superset.chatbot', name: 'Superset Chatbot' },
+      CHATBOT_LOCATION,
+      () => React.createElement(FailingChatbot),
+    ),
+  );
+
+  // The host-owned error boundary catches the failure; render does not throw.
+  expect(() => render(<ChatbotMount />)).not.toThrow();
+});

superset-frontend/src/components/ChatbotMount/index.tsx

@@ -0,0 +1,82 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/**
+ * @fileoverview Host mount point for the singleton `superset.chatbot`
+ * contribution area.
+ *
+ * The host owns the slot: a fixed bottom-right anchor that persists across all
+ * routes, with a managed z-index. The extension owns everything rendered
+ * inside it — the collapsed bubble, the expanded panel, all open/close state,
+ * animations, and behavior (SIP §3.2 "Component contract").
+ *
+ * Singleton resolution (which of possibly several registered chatbots renders)
+ * is delegated to `getActiveChatbot`. If no chatbot extension is registered,
+ * this component renders nothing and the corner stays empty.
+ */
+
+import { useState, useEffect } from 'react';
+import { css, useTheme } from '@apache-superset/core/theme';
+import { ErrorBoundary } from 'src/components/ErrorBoundary';
+import { getActiveChatbot } from 'src/core/chatbot';
+import { subscribeToLocation } from 'src/core/views';
+import { CHATBOT_LOCATION } from 'src/views/contributions';
+
+const CHATBOT_EDGE_MARGIN = 24;
+
+/**
+ * Renders the active chatbot extension into a fixed bottom-right slot.
+ *
+ * Mounted once at the app root so the bubble persists across routes.
+ * Re-resolves when the chatbot registry changes (extension activated or
+ * deactivated at runtime via the P1.A lifecycle contract).
+ * Renders null when no chatbot extension is registered.
+ */
+const ChatbotMount = () => {
+  const theme = useTheme();
+  const [activeChatbot, setActiveChatbot] = useState(getActiveChatbot);
+
+  useEffect(
+    () =>
+      subscribeToLocation(CHATBOT_LOCATION, () =>
+        setActiveChatbot(getActiveChatbot()),
+      ),
+    [],
+  );
+
+  if (!activeChatbot) {
+    return null;
+  }
+
+  return (
+    <div
+      data-test="chatbot-mount"
+      css={css`
+        position: fixed;
+        right: ${CHATBOT_EDGE_MARGIN}px;
+        bottom: ${CHATBOT_EDGE_MARGIN}px;
+        /* Above dashboard content and the toast layer, below modal dialogs. */
+        z-index: ${theme.zIndexPopupBase + 2};
+      `}
+    >
+      <ErrorBoundary>{activeChatbot.provider()}</ErrorBoundary>
+    </div>
+  );
+};
+
+export default ChatbotMount;

superset-frontend/src/core/chatbot/index.test.ts

@@ -0,0 +1,96 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import React from 'react';
+import { views } from 'src/core/views';
+import { CHATBOT_LOCATION } from 'src/views/contributions';
+import { getActiveChatbot } from './index';
+
+const disposables: Array<{ dispose: () => void }> = [];
+
+afterEach(() => {
+  disposables.forEach(d => d.dispose());
+  disposables.length = 0;
+});
+
+test('getActiveChatbot returns undefined when no chatbot is registered', () => {
+  expect(getActiveChatbot()).toBeUndefined();
+});
+
+test('getActiveChatbot resolves the single registered chatbot', () => {
+  const provider = () => React.createElement('div', null, 'Chatbot');
+  disposables.push(
+    views.registerView(
+      { id: 'superset.chatbot', name: 'Superset Chatbot' },
+      CHATBOT_LOCATION,
+      provider,
+    ),
+  );
+
+  const active = getActiveChatbot();
+  expect(active).toEqual({ id: 'superset.chatbot', provider });
+});
+
+test('getActiveChatbot picks the first-to-register when multiple are installed', () => {
+  const firstProvider = () => React.createElement('div', null, 'First');
+  const secondProvider = () => React.createElement('div', null, 'Second');
+  disposables.push(
+    views.registerView(
+      { id: 'first.chatbot', name: 'First Chatbot' },
+      CHATBOT_LOCATION,
+      firstProvider,
+    ),
+    views.registerView(
+      { id: 'second.chatbot', name: 'Second Chatbot' },
+      CHATBOT_LOCATION,
+      secondProvider,
+    ),
+  );
+
+  const active = getActiveChatbot();
+  expect(active?.id).toBe('first.chatbot');
+  expect(active?.provider).toBe(firstProvider);
+});
+
+test('getActiveChatbot ignores views registered at other locations', () => {
+  const provider = () => React.createElement('div', null, 'Panel');
+  disposables.push(
+    views.registerView(
+      { id: 'some.panel', name: 'Some Panel' },
+      'sqllab.panels',
+      provider,
+    ),
+  );
+
+  expect(getActiveChatbot()).toBeUndefined();
+});
+
+test('getActiveChatbot stops resolving a chatbot once it is disposed', () => {
+  const provider = () => React.createElement('div', null, 'Chatbot');
+  const disposable = views.registerView(
+    { id: 'superset.chatbot', name: 'Superset Chatbot' },
+    CHATBOT_LOCATION,
+    provider,
+  );
+
+  expect(getActiveChatbot()?.id).toBe('superset.chatbot');
+
+  disposable.dispose();
+
+  expect(getActiveChatbot()).toBeUndefined();
+});

superset-frontend/src/core/chatbot/index.ts

@@ -0,0 +1,77 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/**
+ * @fileoverview Host-internal resolver for the exclusive `superset.chatbot`
+ * contribution area.
+ *
+ * `superset.chatbot` is a singleton contribution area: multiple chatbot
+ * extensions may register a view there, but the host renders exactly one.
+ * This module owns the host-side selection policy.
+ *
+ * This is host-internal infrastructure — it is NOT part of the public
+ * `@apache-superset/core` API. Extensions register via the public
+ * `views.registerView()`; only the host resolves which one is active.
+ */
+
+import { ReactElement } from 'react';
+import { CHATBOT_LOCATION } from 'src/views/contributions';
+import { getRegisteredViewIds, getViewProvider } from 'src/core/views';
+
+/**
+ * The resolved active chatbot: a view id paired with its renderable provider.
+ */
+export interface ActiveChatbot {
+  /** The registered view id of the selected chatbot. */
+  id: string;
+  /** The provider that renders the chatbot's React element. */
+  provider: () => ReactElement;
+}
+
+/**
+ * Resolves which single chatbot extension is currently active.
+ *
+ * Selection policy (P1):
+ *  - If no chatbot is registered, returns `undefined` — the corner stays empty.
+ *  - If one or more chatbots are registered, the first one to register wins.
+ *
+ * `Set` preserves insertion order, so "first to register" is deterministic.
+ *
+ * This is the P1 fallback policy. P2 introduces an admin "Default chatbot"
+ * setting (SIP §4 option (c)); when that lands, the admin-selected id takes
+ * precedence here and this first-to-register behavior remains only as the
+ * fallback used when no admin setting is configured.
+ *
+ * @returns The active chatbot's id and provider, or `undefined` if none.
+ */
+export const getActiveChatbot = (): ActiveChatbot | undefined => {
+  const registeredIds = getRegisteredViewIds(CHATBOT_LOCATION);
+  if (registeredIds.length === 0) {
+    return undefined;
+  }
+
+  // Deterministic first-to-register fallback. P2 will consult the admin
+  // "Default chatbot" setting before this point.
+  const [selectedId] = registeredIds;
+  const provider = getViewProvider(CHATBOT_LOCATION, selectedId);
+  if (!provider) {
+    return undefined;
+  }
+
+  return { id: selectedId, provider };
+};

superset-frontend/src/core/views/index.test.ts

@@ -17,7 +17,12 @@
  * under the License.
  */
 import React from 'react';
-import { views, resolveView } from './index';
+import {
+  views,
+  resolveView,
+  getViewProvider,
+  getRegisteredViewIds,
+} from './index';
 
 const disposables: Array<{ dispose: () => void }> = [];
 
@@ -110,3 +115,59 @@ test('dispose removes the view registration', () => {
 
   expect(views.getViews('sqllab.panels')).toBeUndefined();
 });
+
+test('getViewProvider returns the registered provider for a matching location', () => {
+  const provider = () => React.createElement('div', null, 'Test');
+  disposables.push(
+    views.registerView(
+      { id: 'test.provider', name: 'Test Provider' },
+      'superset.chatbot',
+      provider,
+    ),
+  );
+
+  expect(getViewProvider('superset.chatbot', 'test.provider')).toBe(provider);
+});
+
+test('getViewProvider returns undefined when the location does not match', () => {
+  const provider = () => React.createElement('div', null, 'Test');
+  disposables.push(
+    views.registerView(
+      { id: 'test.provider', name: 'Test Provider' },
+      'sqllab.panels',
+      provider,
+    ),
+  );
+
+  // Registered, but at a different location.
+  expect(getViewProvider('superset.chatbot', 'test.provider')).toBeUndefined();
+});
+
+test('getViewProvider returns undefined for an unknown id', () => {
+  expect(getViewProvider('superset.chatbot', 'nonexistent')).toBeUndefined();
+});
+
+test('getRegisteredViewIds returns ids in registration order', () => {
+  const provider = () => React.createElement('div', null, 'Test');
+  disposables.push(
+    views.registerView(
+      { id: 'first.chatbot', name: 'First' },
+      'superset.chatbot',
+      provider,
+    ),
+    views.registerView(
+      { id: 'second.chatbot', name: 'Second' },
+      'superset.chatbot',
+      provider,
+    ),
+  );
+
+  expect(getRegisteredViewIds('superset.chatbot')).toEqual([
+    'first.chatbot',
+    'second.chatbot',
+  ]);
+});
+
+test('getRegisteredViewIds returns an empty array for an unused location', () => {
+  expect(getRegisteredViewIds('superset.chatbot')).toEqual([]);
+});

superset-frontend/src/core/views/index.ts

@@ -39,6 +39,27 @@ const viewRegistry: Map<
 
 const locationIndex: Map<string, Set<string>> = new Map();
 
+/** Listeners notified whenever a view is registered or unregistered at a location. */
+const locationListeners: Map<string, Set<() => void>> = new Map();
+
+const notifyListeners = (location: string) => {
+  locationListeners.get(location)?.forEach(fn => fn());
+};
+
+/**
+ * Subscribe to registration changes at a specific location.
+ * Returns an unsubscribe function.
+ */
+export const subscribeToLocation = (
+  location: string,
+  listener: () => void,
+): (() => void) => {
+  const listeners = locationListeners.get(location) ?? new Set();
+  listeners.add(listener);
+  locationListeners.set(location, listeners);
+  return () => listeners.delete(listener);
+};
+
 const registerView: typeof viewsApi.registerView = (
   view: View,
   location: string,
@@ -52,9 +73,12 @@ const registerView: typeof viewsApi.registerView = (
   ids.add(id);
   locationIndex.set(location, ids);
 
+  notifyListeners(location);
+
   return new Disposable(() => {
     viewRegistry.delete(id);
     locationIndex.get(location)?.delete(id);
+    notifyListeners(location);
   });
 };
 
@@ -77,6 +101,53 @@ const getViews: typeof viewsApi.getViews = (
     .filter((c): c is View => !!c);
 };
 
+/**
+ * Host-internal accessor that returns the registered `provider` for a view id
+ * at a given location.
+ *
+ * This is deliberately NOT part of the public `@apache-superset/core` `views`
+ * API. The public `getViews` returns descriptors only (`id`/`name`/...), so an
+ * extension can discover what is registered but cannot obtain — and therefore
+ * cannot render — another extension's view outside the host's mount point,
+ * lifecycle, and fault-isolation boundary.
+ *
+ * The host uses this accessor to render exclusive (singleton) contribution
+ * areas such as `superset.chatbot`, where it must enumerate the candidates and
+ * then render exactly one. See `getActiveChatbot` in `src/core/chatbot`.
+ *
+ * @param location The contribution location (e.g. `superset.chatbot`).
+ * @param id The registered view id.
+ * @returns The provider function, or undefined if no matching view is
+ *   registered at that location.
+ */
+export const getViewProvider = (
+  location: string,
+  id: string,
+): (() => ReactElement) | undefined => {
+  const entry = viewRegistry.get(id);
+  if (entry?.location !== location) {
+    return undefined;
+  }
+  return entry.provider;
+};
+
+/**
+ * Host-internal accessor that returns the ordered list of view ids registered
+ * at a location, in registration order.
+ *
+ * Registration order is meaningful for exclusive locations: the host's
+ * deterministic fallback policy ("first to register wins") relies on it.
+ * Like {@link getViewProvider}, this is host-internal and not part of the
+ * public API.
+ *
+ * @param location The contribution location.
+ * @returns View ids in registration order, or an empty array if none.
+ */
+export const getRegisteredViewIds = (location: string): string[] => {
+  const ids = locationIndex.get(location);
+  return ids ? Array.from(ids) : [];
+};
+
 export const views: typeof viewsApi = {
   registerView,
   getViews,

superset-frontend/src/extensions/ExtensionsLoader.ts

@@ -17,8 +17,11 @@
  * under the License.
  */
 import { SupersetClient } from '@superset-ui/core';
+import { t } from '@apache-superset/core/translation';
 import { logging } from '@apache-superset/core/utils';
 import type { common as core } from '@apache-superset/core';
+import { addDangerToast } from 'src/components/MessageToasts/actions';
+import { store } from 'src/views/store';
 
 type Extension = core.Extension;
 
@@ -36,6 +39,9 @@ class ExtensionsLoader {
 
   private initializationPromise: Promise<void> | null = null;
 
+  /** Disposables returned by contribution registrations, keyed by extension id. */
+  private extensionDisposables: Map<string, (() => void)[]> = new Map();
+
   // eslint-disable-next-line no-useless-constructor
   private constructor() {
     // Private constructor for singleton pattern
@@ -88,7 +94,8 @@ class ExtensionsLoader {
   public async initializeExtension(extension: Extension) {
     try {
       if (extension.remoteEntry) {
-        await this.loadModule(extension);
+        const disposables = await this.loadModule(extension);
+        this.extensionDisposables.set(extension.id, disposables);
       }
       this.extensionIndex.set(extension.id, extension);
     } catch (error) {
@@ -96,15 +103,31 @@ class ExtensionsLoader {
         `Failed to initialize extension ${extension.name}\n`,
         error,
       );
+      store.dispatch(
+        addDangerToast(t('Extension "%s" failed to load.', extension.name)),
+      );
     }
   }
 
+  /**
+   * Deactivates an extension by disposing all of its registered contributions
+   * and removing it from the index.
+   */
+  public deactivateExtension(id: string): void {
+    const disposables = this.extensionDisposables.get(id);
+    if (disposables) {
+      disposables.forEach(dispose => dispose());
+      this.extensionDisposables.delete(id);
+    }
+    this.extensionIndex.delete(id);
+  }
+
   /**
    * Loads a single extension module via webpack module federation.
    * The module's top-level side effects fire contribution registrations.
    * @param extension The extension to load.
    */
-  private async loadModule(extension: Extension): Promise<void> {
+  private async loadModule(extension: Extension): Promise<(() => void)[]> {
     const { remoteEntry, id } = extension;
 
     // Load the remote entry script
@@ -149,8 +172,33 @@ class ExtensionsLoader {
     await container.init(__webpack_share_scopes__.default);
 
     const factory = await container.get('./index');
-    // Execute the module factory - side effects fire registrations
-    factory();
+
+    // Intercept contribution registrations during module activation so we can
+    // collect the Disposables and drive cleanup on deactivation.
+    const collected: (() => void)[] = [];
+    const originalSuperset = window.superset;
+    window.superset = {
+      ...originalSuperset,
+      views: {
+        ...originalSuperset.views,
+        registerView: (
+          ...args: Parameters<typeof originalSuperset.views.registerView>
+        ) => {
+          const disposable = originalSuperset.views.registerView(...args);
+          collected.push(() => disposable.dispose());
+          return disposable;
+        },
+      },
+    };
+
+    try {
+      // Execute the module factory — side effects fire contribution registrations
+      factory();
+    } finally {
+      window.superset = originalSuperset;
+    }
+
+    return collected;
   }
 
   /**

superset-frontend/src/extensions/ExtensionsStartup.tsx

@@ -19,6 +19,7 @@
 import { useEffect, useState } from 'react';
 // eslint-disable-next-line no-restricted-syntax
 import * as supersetCore from '@apache-superset/core';
+import { logging } from '@apache-superset/core/utils';
 import { FeatureFlag, isFeatureEnabled } from '@superset-ui/core';
 import {
   authentication,
@@ -80,14 +81,29 @@ const ExtensionsStartup: React.FC<{ children?: React.ReactNode }> = ({
       views,
     };
 
-    const setup = async () => {
-      if (isFeatureEnabled(FeatureFlag.EnableExtensions)) {
-        await ExtensionsLoader.getInstance().initializeExtensions();
-      }
-      setInitialized(true);
+    // Isolate unhandled rejections that originate from extension code so they
+    // cannot crash the host application. Extensions load via Module Federation
+    // and their async failures (e.g. failed API calls, unhandled promise
+    // chains) would otherwise surface as uncaught rejections in the host.
+    const handleUnhandledRejection = (event: PromiseRejectionEvent) => {
+      // Always log so extension authors can diagnose failures.
+      logging.error('[extensions] Unhandled rejection from extension:', event.reason);
+      event.preventDefault();
     };
+    window.addEventListener('unhandledrejection', handleUnhandledRejection);
 
-    setup();
+    // Render the host immediately; extension bundles load in the background.
+    // ChatbotMount re-resolves reactively once the chatbot extension registers
+    // (via subscribeToLocation), so the bubble appears without blocking the UI.
+    setInitialized(true);
+
+    if (isFeatureEnabled(FeatureFlag.EnableExtensions)) {
+      ExtensionsLoader.getInstance().initializeExtensions();
+    }
+
+    return () => {
+      window.removeEventListener('unhandledrejection', handleUnhandledRejection);
+    };
   }, [initialized, userId]);
 
   if (!initialized) {

superset-frontend/src/views/App.tsx

@@ -39,6 +39,7 @@ import setupCodeOverrides from 'src/setup/setupCodeOverrides';
 import { logEvent } from 'src/logger/actions';
 import { store } from 'src/views/store';
 import ExtensionsStartup from 'src/extensions/ExtensionsStartup';
+import ChatbotMount from 'src/components/ChatbotMount';
 import { RootContextProviders } from './RootContextProviders';
 import { ScrollToTop } from './ScrollToTop';
 
@@ -112,6 +113,13 @@ const App = () => (
             </Route>
           ))}
         </Switch>
+        {/*
+          The singleton chatbot bubble. Rendered as a sibling of the route
+          Switch — inside ExtensionsStartup so chatbot extensions have been
+          loaded and registered, but outside the Switch so the bubble persists
+          across route changes (SIP §3.2).
+        */}
+        <ChatbotMount />
       </ExtensionsStartup>
       <ToastContainer />
     </RootContextProviders>

superset-frontend/src/views/contributions.ts

@@ -0,0 +1,31 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/**
+ * View locations for app-shell extension integration.
+ *
+ * These define locations that persist across all routes, mirroring the `app`
+ * scope of the `ViewContributions` manifest schema.
+ */
+export const AppViewLocations = {
+  app: {
+    chatbot: 'superset.chatbot',
+  },
+} as const;
+
+export const CHATBOT_LOCATION = AppViewLocations.app.chatbot;