feat(billing): plan taxonomy reconciliation + Stripe sync + internal-tester allowlist (#164)

Co-authored-by: Michael Chihlas <michael@resolutionflow.com>
Co-committed-by: Michael Chihlas <michael@resolutionflow.com>

backend/app/api/endpoints/config.py

@@ -11,22 +11,31 @@ frontend codegen and other call sites if needed.
 
 from __future__ import annotations
 
-from fastapi import APIRouter
+from typing import Annotated, Optional
 
+from fastapi import APIRouter, Depends
+
+from app.api.deps import get_current_user_optional
 from app.core.config import settings
+from app.models.user import User
 from app.schemas.config import PublicConfigResponse
 
 router = APIRouter(prefix="/config", tags=["config"])
 
 
 @router.get("/public", response_model=PublicConfigResponse)
-async def get_public_config() -> PublicConfigResponse:
+async def get_public_config(
+    current_user: Annotated[Optional[User], Depends(get_current_user_optional)],
+) -> PublicConfigResponse:
     """Return public-safe runtime config.
 
     `oauth_providers` reflects which OAuth client IDs are configured server
     side; the frontend uses it to render only buttons that will actually
     succeed. `self_serve_enabled` is the master switch for the new public
-    self-serve signup flow.
+    self-serve signup flow; an authenticated caller whose email is on the
+    INTERNAL_TESTER_EMAILS allowlist sees `True` even when the global flag
+    is off, so internal validation in prod test mode can exercise the full
+    surface before the public flip.
     """
     providers: list[str] = []
     if settings.GOOGLE_CLIENT_ID:
@@ -34,7 +43,8 @@ async def get_public_config() -> PublicConfigResponse:
     if settings.MS_CLIENT_ID:
         providers.append("microsoft")
 
+    user_email = current_user.email if current_user else None
     return PublicConfigResponse(
-        self_serve_enabled=settings.SELF_SERVE_ENABLED,
+        self_serve_enabled=settings.is_self_serve_active_for(user_email),
         oauth_providers=providers,
     )