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/views/share.py

@@ -23,6 +23,7 @@ templates = Jinja2Templates(directory=str(_templates_dir))
 async def shared_link_view(request: Request, token: str):
     """Render the public share landing page for a given token."""
     return templates.TemplateResponse(
+        request,
         "shared_link_view.html",
-        {"request": request, "token": token},
+        context={"token": token},
     )