[yeongseon]

Summary

Explain the native FunctionApp versus FastAPI-on-AsgiFunctionApp architecture choice fairly.

Changes

• Describe native bindings, ASGI routing, middleware, dependency injection and validation boundaries.
• Link the official Azure sample (identified as archived) and current AsgiFunctionApp API documentation.
• Replace the misleading standalone comparison and avoid unmeasured performance claims.
• Align product positioning and the docs landing page.

Validation

• Verified hosting against the official Azure sample and API reference and FastAPI features documentation; package boundaries against implementation.
• make check-all passed: 1650 passed, 30 skipped, 22 deselected, 5 warnings in 29.39s; coverage 95.25%.
• make docs passed with strict mode. The commit hook additionally normalized one pre-existing code-block indentation.
• GitHub CI pending.

Related Issues

Closes #847

Merge authorized by the maintainer’s explicit instruction.