fix: adapt TemplateResponse calls to Starlette 1.0 new-style API

Starlette 1.0.0 changed TemplateResponse signature from
(name, context_dict) to (request, name, context=dict).

- Update base.py wrapper to convert old-style calls to new-style
- Update main.py error handler TemplateResponse calls
- Update local_auth.py, billing.py, auth.py, share.py calls
- Update test mocks for new calling convention

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
Agent-Logs-Url: https://github.com/christianlouis/DocuElevate/sessions/7b5f7e0d-89ad-43be-b68d-a9c0c5407a7e

app/api/billing.py

@@ -260,7 +260,7 @@ async def stripe_webhook(request: Request, db: Session = Depends(get_db)) -> dic
 @require_login
 async def billing_success(request: Request) -> Any:
     """Show a success page after a completed Stripe Checkout."""
-    return _templates.TemplateResponse("billing_success.html", {"request": request})
+    return _templates.TemplateResponse(request, "billing_success.html")
 
 
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