Fix linting issues with ruff --fix

Applied automatic fixes for 315 out of 597 linting errors:
- Remove unused imports (F401)
- Fix f-string without placeholders (F541)
- Split multiple imports (E401)
- Remove redundant import aliases

Remaining 272 errors are mostly style issues:
- 164 E701: Multiple statements on one line (colon)
- 70 E402: Module import not at top of file
- 13 F841: Unused variables
- Various other style warnings

Code functionality unchanged - all fixes are cosmetic improvements.

mcp_auth_http_adapter.py

@@ -18,7 +18,7 @@ from fastapi.responses import RedirectResponse, JSONResponse
 try:
     from clerk_backend_api import Clerk
     CLERK_AVAILABLE = True
-except ImportError as e:
+except ImportError:
     CLERK_AVAILABLE = False
     Clerk = None