Automate stable REST API permission reference doc generation

[durgaprasadml]

Automate stable REST API permission reference doc generation.

This PR introduces an automated extractor for stable REST API permissions and generates a reference RST document directly from the source routes and permission declarations.

Current implementation:

• statically analyzes /api/v2 route definitions
• extracts requires_access_* permission metadata
• generates api_permissions_ref.rst
• includes regression and invariant tests
• integrates with existing prek-based generation workflows

This PR is intentionally opened as a draft to gather maintainer feedback on:

• AST-based extraction vs runtime introspection
• final file placement
• generation workflow integration
• committed generated artifacts

Closes: #10937

[boring-cyborg]

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