fix(docs): tighten onBrokenLinks to throw and fix surfaced broken links

Previously docusaurus.config.ts had `onBrokenLinks: 'warn'`, so broken
internal links produced advisory warnings during build but didn't gate
merges. Tightening to `throw` surfaces every broken internal route at
build time. Three classes of issue fell out:

1. Stale `/docs/...` and `/docs/6.0.0/...` references in the 6.0.0
   versioned snapshot. The user-facing docs section was renamed
   `docs` → `user-docs` (routeBasePath) at some point after 6.0.0 was
   cut, but the snapshot's links still pointed at the old prefix. The
   live site redirects /docs/* → /user-docs/* at runtime, but
   Docusaurus's onBrokenLinks checker doesn't honor redirects.
   Bulk-rewrote /docs/* → /user-docs/* across the snapshot (and one
   /docs/api → /developer-docs/api).

2. Bare-relative MDX links like `[Label](./mcp)` (no .md/.mdx
   extension). Docusaurus renders an absolute href in SSR HTML, so
   static crawlers see correct links — BUT React Router's `<Link>`
   component on the client side resolves the bare path relative to
   the current URL on click, so when the page URL has a trailing
   slash (e.g. /extensions/overview/), `./mcp` becomes
   /extensions/overview/mcp (404). This is exactly the broken-flow a
   user reported on /developer-docs/extensions/overview/. Added the
   `.md`/`.mdx` extension to all 44 such links across 17 files; this
   makes Docusaurus resolve them to the canonical doc URL at the
   <Link> level, so SPA navigation works regardless of trailing slash.

3. Miscellaneous content fixes:
   - 4 `/configuration/feature-flags` references in 6.0.0 snapshot
     pointed at a page that doesn't exist in that version (the
     dedicated feature-flags page was added later). Repointed to the
     `#feature-flags` anchor inside `configuring-superset.mdx`.
   - 3 references to `superset-core/src/superset_core/rest_api/decorators.py`
     in extensions docs were rendered as relative URLs, resolving to
     /developer-docs/extensions/superset-core/... (404). Converted to
     absolute GitHub URLs.
   - 1 `/storybook/?path=...` link in extensions/components/index.mdx
     pointed at a non-existent route. Repointed to the existing
     `/developer-docs/testing/storybook` page that explains how to
     run Storybook locally.
   - 4 unclosed-paren markdown links in 6.0.0 installation-methods.mdx
     (pre-existing source bugs).

Build now passes with `onBrokenLinks: 'throw'`. Note that
`onBrokenAnchors` is still `'warn'` (default); a separate effort
should tighten that and fix the surviving anchor warnings (currently
~60 instances of `/community#superset-community-calendar`).

docs/developer_docs/contributing/code-review.md

@@ -336,4 +336,4 @@ stats.sort_stats('cumulative').print_stats(10)
 - [Best Practices for Code Review](https://smartbear.com/learn/code-review/best-practices-for-peer-code-review/)
 - [The Art of Readable Code](https://www.oreilly.com/library/view/the-art-of/9781449318482/)
 
-Next: [Reporting issues effectively](./issue-reporting)
+Next: [Reporting issues effectively](./issue-reporting.md)

docs/developer_docs/contributing/issue-reporting.md

@@ -413,6 +413,6 @@ Consider:
 - **Feature Request**: Use feature request template
 - **Question**: Use GitHub Discussions
 - **Configuration Help**: Ask in Slack
-- **Development Help**: See [Contributing Guide](./overview)
+- **Development Help**: See [Contributing Guide](./overview.md)
 
-Next: [Understanding the release process](./release-process)
+Next: [Understanding the release process](./release-process.md)

docs/developer_docs/contributing/overview.md

@@ -158,9 +158,9 @@ Security team members should also follow these general expectations:
 
 Ready to contribute? Here's how to get started:
 
-1. **[Set up your environment](./development-setup)** - Get Superset running locally
+1. **[Set up your environment](./development-setup.md)** - Get Superset running locally
 2. **[Find something to work on](#types-of-contributions)** - Pick an issue or feature
-3. **[Submit your contribution](./submitting-pr)** - Create a pull request
-4. **[Follow guidelines](./guidelines)** - Ensure code quality
+3. **[Submit your contribution](./submitting-pr.md)** - Create a pull request
+4. **[Follow guidelines](./guidelines.md)** - Ensure code quality
 
 Welcome to the Apache Superset community! 🚀

docs/developer_docs/contributing/release-process.md

@@ -466,4 +466,4 @@ Credit:
 - [Release Scripts](https://github.com/apache/superset/tree/master/scripts/release)
 - [Superset Repository Scripts](https://github.com/apache/superset/tree/master/scripts)
 
-Next: Return to [Contributing Overview](./overview)
+Next: Return to [Contributing Overview](./overview.md)

docs/developer_docs/contributing/submitting-pr.md

@@ -31,7 +31,7 @@ Learn how to create and submit high-quality pull requests to Apache Superset.
 ### Prerequisites
 - [ ] Development environment is set up
 - [ ] You've forked and cloned the repository
-- [ ] You've read the [contributing overview](./overview)
+- [ ] You've read the [contributing overview](./overview.md)
 - [ ] You've found or created an issue to work on
 
 ### PR Readiness Checklist
@@ -318,4 +318,4 @@ git push origin master
 - **GitHub**: Tag @apache/superset-committers for attention
 - **Mailing List**: dev@superset.apache.org
 
-Next: [Understanding code review process](./code-review)
+Next: [Understanding code review process](./code-review.md)

docs/developer_docs/extensions/architecture.md

@@ -233,7 +233,7 @@ This architecture provides several key benefits:
 
 Now that you understand the architecture, explore:
 
-- **[Dependencies](./dependencies)** - Managing dependencies and understanding API stability
-- **[Quick Start](./quick-start)** - Build your first extension
-- **[Contribution Types](./contribution-types)** - What kinds of extensions you can build
-- **[Development](./development)** - Project structure, APIs, and development workflow
+- **[Dependencies](./dependencies.md)** - Managing dependencies and understanding API stability
+- **[Quick Start](./quick-start.md)** - Build your first extension
+- **[Contribution Types](./contribution-types.md)** - What kinds of extensions you can build
+- **[Development](./development.md)** - Project structure, APIs, and development workflow

docs/developer_docs/extensions/components/index.mdx

@@ -29,7 +29,7 @@ These UI components are available to Superset extension developers through the `
 
 ## Available Components
 
-- [Alert](./alert)
+- [Alert](./alert.mdx)
 
 ## Usage
 
@@ -90,4 +90,4 @@ InteractiveMyComponent.argTypes = {
 
 ## Interactive Documentation
 
-For interactive examples with controls, visit the [Storybook](/storybook/?path=/docs/extension-components--docs).
+For interactive examples with controls, run Storybook locally — see the [Storybook documentation](/developer-docs/testing/storybook).

docs/developer_docs/extensions/contribution-types.md

@@ -146,7 +146,7 @@ class MyExtensionAPI(RestApi):
 from .api import MyExtensionAPI
 ```
 
-**Note**: The [`@api`](superset-core/src/superset_core/rest_api/decorators.py) decorator automatically detects context and generates appropriate paths:
+**Note**: The [`@api`](https://github.com/apache/superset/blob/master/superset-core/src/superset_core/rest_api/decorators.py) decorator automatically detects context and generates appropriate paths:
 
 - **Extension context**: `/extensions/{publisher}/{name}/` with ID prefixed as `extensions.{publisher}.{name}.{id}`
 - **Host context**: `/api/v1/` with original ID
@@ -193,7 +193,7 @@ def get_summary() -> dict:
     return {"status": "success", "result": {"queries_today": 42}}
 ```
 
-See [MCP Integration](./mcp) for implementation details.
+See [MCP Integration](./mcp.md) for implementation details.
 
 ### MCP Prompts
 
@@ -223,7 +223,7 @@ async def analysis_guide(ctx: Context) -> str:
     """
 ```
 
-See [MCP Integration](./mcp) for implementation details.
+See [MCP Integration](./mcp.md) for implementation details.
 
 ### Semantic Layers
 

docs/developer_docs/extensions/dependencies.md

@@ -161,6 +161,6 @@ Until then, monitor the Superset release notes and test your extensions with eac
 
 ## Next Steps
 
-- **[Architecture](./architecture)** - Understand the extension system design
-- **[Development](./development)** - Learn about APIs and development workflow
-- **[Quick Start](./quick-start)** - Build your first extension
+- **[Architecture](./architecture.md)** - Understand the extension system design
+- **[Development](./development.md)** - Learn about APIs and development workflow
+- **[Quick Start](./quick-start.md)** - Build your first extension

docs/developer_docs/extensions/development.md

@@ -252,7 +252,7 @@ class DatasetReferencesAPI(RestApi):
 
 ### Automatic Context Detection
 
-The [`@api`](superset-core/src/superset_core/rest_api/decorators.py) decorator automatically detects whether it's being used in host or extension code:
+The [`@api`](https://github.com/apache/superset/blob/master/superset-core/src/superset_core/rest_api/decorators.py) decorator automatically detects whether it's being used in host or extension code:
 
 - **Extension APIs**: Registered under `/extensions/{publisher}/{name}/` with IDs prefixed as `extensions.{publisher}.{name}.{id}`
 - **Host APIs**: Registered under `/api/v1/` with original IDs

docs/developer_docs/extensions/extension-points/editors.md

@@ -217,6 +217,6 @@ const disposable = handle.registerCompletionProvider(provider);
 
 ## Next Steps
 
-- **[SQL Lab Extension Points](./sqllab)** - Learn about other SQL Lab customizations
+- **[SQL Lab Extension Points](./sqllab.md)** - Learn about other SQL Lab customizations
 - **[Contribution Types](../contribution-types)** - Explore other contribution types
 - **[Development](../development)** - Set up your development environment

docs/developer_docs/extensions/extension-points/sqllab.md

@@ -51,7 +51,7 @@ SQL Lab provides 4 extension points where extensions can contribute custom UI co
 | **Right Sidebar** | `sqllab.rightSidebar` | ✓     | —     | Custom panels (AI assistants, query analysis)  |
 | **Panels**        | `sqllab.panels`       | ✓     | ✓     | Custom tabs + toolbar actions (data profiling) |
 
-\*Editor views are contributed via [Editor Contributions](./editors), not standard view contributions.
+\*Editor views are contributed via [Editor Contributions](./editors.md), not standard view contributions.
 
 ## Customization Types
 
@@ -78,7 +78,7 @@ Extensions can add toolbar actions to **Left Sidebar**, **Editor**, and **Panels
 
 ### Custom Editors
 
-Extensions can replace the default SQL editor with custom implementations (Monaco, CodeMirror, etc.). See [Editor Contributions](./editors) for details.
+Extensions can replace the default SQL editor with custom implementations (Monaco, CodeMirror, etc.). See [Editor Contributions](./editors.md) for details.
 
 ## Examples
 

docs/developer_docs/extensions/mcp.md

@@ -455,5 +455,5 @@ async def metrics_guide(ctx: Context) -> str:
 
 ## Next Steps
 
-- **[Development](./development)** - Project structure, APIs, and dev workflow
-- **[Security](./security)** - Security best practices for extensions
+- **[Development](./development.md)** - Project structure, APIs, and dev workflow
+- **[Security](./security.md)** - Security best practices for extensions

docs/developer_docs/extensions/overview.md

@@ -47,13 +47,13 @@ Extension developers have access to pre-built UI components via `@apache-superse
 
 ## Next Steps
 
-- **[Quick Start](./quick-start)** - Build your first extension with a complete walkthrough
-- **[Architecture](./architecture)** - Design principles and system overview
-- **[Dependencies](./dependencies)** - Managing dependencies and understanding API stability
-- **[Contribution Types](./contribution-types)** - Available extension points
-- **[Development](./development)** - Project structure, APIs, and development workflow
-- **[Deployment](./deployment)** - Packaging and deploying extensions
-- **[MCP Integration](./mcp)** - Adding AI agent capabilities using extensions
-- **[Security](./security)** - Security considerations and best practices
-- **[Tasks](./tasks)** - Framework for creating and managing long running tasks
-- **[Community Extensions](./registry)** - Browse extensions shared by the community
+- **[Quick Start](./quick-start.md)** - Build your first extension with a complete walkthrough
+- **[Architecture](./architecture.md)** - Design principles and system overview
+- **[Dependencies](./dependencies.md)** - Managing dependencies and understanding API stability
+- **[Contribution Types](./contribution-types.md)** - Available extension points
+- **[Development](./development.md)** - Project structure, APIs, and development workflow
+- **[Deployment](./deployment.md)** - Packaging and deploying extensions
+- **[MCP Integration](./mcp.md)** - Adding AI agent capabilities using extensions
+- **[Security](./security.md)** - Security considerations and best practices
+- **[Tasks](./tasks.md)** - Framework for creating and managing long running tasks
+- **[Community Extensions](./registry.md)** - Browse extensions shared by the community

docs/developer_docs/extensions/quick-start.md

@@ -168,7 +168,7 @@ class HelloWorldAPI(RestApi):
 
 **Key points:**
 
-- Uses [`@api`](superset-core/src/superset_core/rest_api/decorators.py) decorator with automatic context detection
+- Uses [`@api`](https://github.com/apache/superset/blob/master/superset-core/src/superset_core/rest_api/decorators.py) decorator with automatic context detection
 - Extends `RestApi` from `superset_core.rest_api.api`
 - Uses Flask-AppBuilder decorators (`@expose`, `@protect`, `@safe`)
 - Returns responses using `self.response(status_code, result=data)`
@@ -184,7 +184,7 @@ Replace the generated print statement with API import to trigger registration:
 from .api import HelloWorldAPI  # noqa: F401
 ```
 
-The [`@api`](superset-core/src/superset_core/rest_api/decorators.py) decorator automatically detects extension context and registers your API with proper namespacing.
+The [`@api`](https://github.com/apache/superset/blob/master/superset-core/src/superset_core/rest_api/decorators.py) decorator automatically detects extension context and registers your API with proper namespacing.
 
 ## Step 5: Create Frontend Component
 
@@ -496,7 +496,7 @@ Superset will extract and validate the extension metadata, load the assets, regi
 Here's what happens when your extension loads:
 
 1. **Superset starts**: Reads `manifest.json` from the `.supx` bundle and loads the backend entrypoint
-2. **Backend registration**: `entrypoint.py` imports your API class, triggering the [`@api`](superset-core/src/superset_core/rest_api/decorators.py) decorator to register it automatically
+2. **Backend registration**: `entrypoint.py` imports your API class, triggering the [`@api`](https://github.com/apache/superset/blob/master/superset-core/src/superset_core/rest_api/decorators.py) decorator to register it automatically
 3. **Frontend loads**: When SQL Lab opens, Superset fetches the remote entry file
 4. **Module Federation**: Webpack loads your extension module and resolves `@apache-superset/core` to `window.superset`
 5. **Registration**: The module executes at load time, calling `views.registerView` to register your panel
@@ -509,9 +509,9 @@ Here's what happens when your extension loads:
 
 Now that you have a working extension, explore:
 
-- **[Development](./development)** - Project structure, APIs, and development workflow
-- **[Contribution Types](./contribution-types)** - Other contribution points beyond panels
-- **[Deployment](./deployment)** - Packaging and deploying your extension
-- **[Security](./security)** - Security best practices for extensions
+- **[Development](./development.md)** - Project structure, APIs, and development workflow
+- **[Contribution Types](./contribution-types.md)** - Other contribution points beyond panels
+- **[Deployment](./deployment.md)** - Packaging and deploying your extension
+- **[Security](./security.md)** - Security best practices for extensions
 
 For a complete real-world example, examine the query insights extension in the Superset codebase.

docs/developer_docs/extensions/security.md

@@ -28,7 +28,7 @@ By default, extensions are disabled and must be explicitly enabled by setting th
 
 For external extensions, administrators are responsible for evaluating and verifying the security of any extensions they choose to install, just as they would when installing third-party NPM or PyPI packages. At this stage, all extensions run in the same context as the host application, without additional sandboxing. This means that external extensions can impact the security and performance of a Superset environment in the same way as any other installed dependency.
 
-We plan to introduce an optional sandboxed execution model for extensions in the future (as part of an additional SIP). Until then, administrators should exercise caution and follow best practices when selecting and deploying third-party extensions. A directory of community extensions is available in the [Community Extensions](./registry) page. Note that these extensions are not vetted by the Apache Superset project—administrators must evaluate each extension before installation.
+We plan to introduce an optional sandboxed execution model for extensions in the future (as part of an additional SIP). Until then, administrators should exercise caution and follow best practices when selecting and deploying third-party extensions. A directory of community extensions is available in the [Community Extensions](./registry.md) page. Note that these extensions are not vetted by the Apache Superset project—administrators must evaluate each extension before installation.
 
 **Any performance or security vulnerabilities introduced by external extensions should be reported directly to the extension author, not as Superset vulnerabilities.**
 

docs/developer_docs/guidelines/frontend/component-style-guidelines.md

@@ -31,7 +31,7 @@ This guide is intended primarily for reusable components. Whenever possible, all
 ## General Guidelines
 
 - We use [Ant Design](https://ant.design/) as our component library. Do not build a new component if Ant Design provides one but rather instead extend or customize what the library provides
-- Always style your component using Emotion and always prefer the theme variables whenever applicable. See: [Emotion Styling Guidelines and Best Practices](./emotion-styling-guidelines)
+- Always style your component using Emotion and always prefer the theme variables whenever applicable. See: [Emotion Styling Guidelines and Best Practices](./emotion-styling-guidelines.md)
 - All components should be made to be reusable whenever possible
 - All components should follow the structure and best practices as detailed below
 

docs/developer_docs/testing/overview.md

@@ -37,16 +37,16 @@ Superset embraces a testing pyramid approach:
 ## Testing Documentation
 
 ### Frontend Testing
-- **[Frontend Testing](./frontend-testing)** - Jest, React Testing Library, and component testing strategies
+- **[Frontend Testing](./frontend-testing.md)** - Jest, React Testing Library, and component testing strategies
 
 ### Backend Testing  
-- **[Backend Testing](./backend-testing)** - pytest, database testing, and API testing patterns
+- **[Backend Testing](./backend-testing.md)** - pytest, database testing, and API testing patterns
 
 ### End-to-End Testing
-- **[E2E Testing](./e2e-testing)** - Playwright testing for complete user workflows
+- **[E2E Testing](./e2e-testing.md)** - Playwright testing for complete user workflows
 
 ### CI/CD Integration
-- **[CI/CD](./ci-cd)** - Continuous integration, automated testing, and deployment pipelines
+- **[CI/CD](./ci-cd.md)** - Continuous integration, automated testing, and deployment pipelines
 
 ## Testing Tools & Frameworks