chore(extensions): simplify backend package structure by removing superset_extensions namespace (#38476)

docs/developer_docs/extensions/development.md

@@ -54,11 +54,10 @@ my-org.dataset-references/
 │   └── package.json
 ├── backend/
 │   ├── src/
-│   │    └── superset_extensions/
-│   │         └── my_org/
-│   │              └── dataset_references/
-│   │                   ├── api.py
-│   │                   └── entrypoint.py
+│   │    └── my_org/
+│   │         └── dataset_references/
+│   │              ├── api.py
+│   │              └── entrypoint.py
 │   ├── pyproject.toml
 │   └── requirements.txt
 ├── dist/
@@ -68,18 +67,17 @@ my-org.dataset-references/
 │   │         ├── remoteEntry.d7a9225d042e4ccb6354.js
 │   │         └── 900.038b20cdff6d49cfa8d9.js
 │   └── backend
-│        └── superset_extensions/
-│             └── my_org/
-│                  └── dataset_references/
-│                       ├── api.py
-│                       └── entrypoint.py
+│        └── my_org/
+│             └── dataset_references/
+│                  ├── api.py
+│                  └── entrypoint.py
 ├── my-org.dataset-references-1.0.0.supx
 └── README.md
 ```
 
 **Note**: With publisher `my-org` and name `dataset-references`, the technical names are:
 - Directory name: `my-org.dataset-references` (kebab-case)
-- Backend Python namespace: `superset_extensions.my_org.dataset_references`
+- Backend Python namespace: `my_org.dataset_references`
 - Backend distribution package: `my_org-dataset_references`
 - Frontend package name: `@my-org/dataset-references` (scoped)
 - Module Federation name: `myOrg_datasetReferences` (camelCase)
@@ -113,7 +111,7 @@ The `extension.json` file contains the metadata necessary for the host applicati
 
 Extensions use standardized entry point locations:
 
-- **Backend**: `backend/src/superset_extensions/{publisher}/{name}/entrypoint.py`
+- **Backend**: `backend/src/{publisher}/{name}/entrypoint.py`
 - **Frontend**: `frontend/src/index.tsx`
 
 ### Build Configuration
@@ -129,7 +127,7 @@ license = "Apache-2.0"
 [tool.apache_superset_extensions.build]
 # Files to include in the extension build/bundle
 include = [
-    "src/superset_extensions/my_org/dataset_references/**/*.py",
+    "src/my_org/dataset_references/**/*.py",
 ]
 exclude = []
 ```

docs/developer_docs/extensions/quick-start.md

@@ -68,7 +68,7 @@ Include backend? [Y/n]: Y
 - **NPM package**: `@my-org/hello-world` (scoped package for frontend distribution)
 - **Module Federation name**: `myOrg_helloWorld` (collision-safe JavaScript identifier)
 - **Backend package**: `my_org-hello_world` (collision-safe Python distribution name)
-- **Python namespace**: `superset_extensions.my_org.hello_world`
+- **Python namespace**: `my_org.hello_world`
 
 This approach ensures that extensions from different organizations cannot conflict, even if they use the same technical name (e.g., both `acme.dashboard-widgets` and `corp.dashboard-widgets` can coexist).
 
@@ -79,10 +79,9 @@ my-org.hello-world/
 ├── extension.json           # Extension metadata and configuration
 ├── backend/                 # Backend Python code
 │   ├── src/
-│   │   └── superset_extensions/
-│   │       └── my_org/
-│   │           └── hello_world/
-│   │               └── entrypoint.py  # Backend registration
+│   │   └── my_org/
+│   │       └── hello_world/
+│   │           └── entrypoint.py  # Backend registration
 │   └── pyproject.toml
 └── frontend/                # Frontend TypeScript/React code
     ├── src/
@@ -116,9 +115,9 @@ The generated `extension.json` contains the extension's metadata.
 
 ## Step 4: Create Backend API
 
-The CLI generated a basic `backend/src/superset_extensions/my_org/hello_world/entrypoint.py`. We'll create an API endpoint.
+The CLI generated a basic `backend/src/my_org/hello_world/entrypoint.py`. We'll create an API endpoint.
 
-**Create `backend/src/superset_extensions/my_org/hello_world/api.py`**
+**Create `backend/src/my_org/hello_world/api.py`**
 
 ```python
 from flask import Response
@@ -176,7 +175,7 @@ class HelloWorldAPI(RestApi):
 - The endpoint will be accessible at `/extensions/my-org/hello-world/message` (automatic extension context)
 - OpenAPI docstrings are crucial - Flask-AppBuilder uses them to automatically generate interactive API documentation at `/swagger/v1`, allowing developers to explore endpoints, understand schemas, and test the API directly from the browser
 
-**Update `backend/src/superset_extensions/my_org/hello_world/entrypoint.py`**
+**Update `backend/src/my_org/hello_world/entrypoint.py`**
 
 Replace the generated print statement with API import to trigger registration: