chore: merge main into branch, resolve conflict in models.py

Both sets of UserProfile columns are retained:
- is_complimentary (from main, migration 019_add_is_complimentary)
- subscription_change_pending_tier / subscription_change_pending_date
  (our branch, renamed to migration 020_add_subscription_change_pending
   with down_revision updated to chain after 019_add_is_complimentary)

app/views/base.py

@@ -32,6 +32,10 @@ def _inject_global_context(ctx: dict) -> None:
     ctx.setdefault("ui_default_color_scheme", getattr(settings, "ui_default_color_scheme", "system"))
     ctx.setdefault("multi_user_enabled", getattr(settings, "multi_user_enabled", False))
     ctx.setdefault("auth_enabled", getattr(settings, "auth_enabled", True))
+    ctx.setdefault(
+        "allow_signup",
+        getattr(settings, "multi_user_enabled", False) and getattr(settings, "allow_local_signup", False),
+    )
 
     req = ctx.get("request")
     if req is not None:

app/views/general.py

@@ -123,6 +123,7 @@ async def serve_index(request: Request, db: Session = Depends(get_db)):
             "user_tier": user_tier,
             "multi_user_enabled": settings.multi_user_enabled,
             "is_admin": is_admin,
+            "allow_signup": settings.multi_user_enabled and settings.allow_local_signup,
         },
     )