Add prompt=none to OAuth authorize, remove propagation chain

Account's authorize endpoint now supports prompt=none: returns
error=login_required redirect when user isn't logged in instead of
bouncing to interactive login. Removed /propagate endpoint since
client apps now detect auth state via prompt=none handshake.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

bp/auth/routes.py

@@ -58,6 +58,7 @@ def register(url_prefix="/auth"):
         redirect_uri = request.args.get("redirect_uri", "")
         state = request.args.get("state", "")
         device_id = request.args.get("device_id", "")
+        prompt = request.args.get("prompt", "")
 
         if client_id not in ALLOWED_CLIENTS:
             return "Invalid client_id", 400
@@ -66,8 +67,12 @@ def register(url_prefix="/auth"):
         if redirect_uri != expected_redirect:
             return "Invalid redirect_uri", 400
 
-        # Not logged in — bounce to magic link login, then back here
+        # Not logged in
         if not g.get("user"):
+            if prompt == "none":
+                # Silent check — no interactive login, return error
+                sep = "&" if "?" in redirect_uri else "?"
+                return redirect(f"{redirect_uri}{sep}error=login_required&state={state}")
             authorize_path = request.full_path
             store_login_redirect_target()
             return redirect(url_for("auth.login_form", next=authorize_path))
@@ -271,52 +276,8 @@ def register(url_prefix="/auth"):
         # Fresh account session ID for grant tracking
         qsession[ACCOUNT_SESSION_KEY] = secrets.token_urlsafe(32)
 
-        # Propagate login to all client apps via OAuth chain
         redirect_url = pop_login_redirect_target()
-        qsession["sso_final"] = redirect_url
-        qsession["sso_chain"] = list(ALLOWED_CLIENTS)
-        return redirect(url_for("auth.propagate"), 303)
-
-    @auth_bp.get("/propagate")
-    @auth_bp.get("/propagate/")
-    async def propagate():
-        """Chain through each client app's OAuth login to create grants
-        and set device cookies.  Dead apps are skipped."""
-        import os, aiohttp
-        from urllib.parse import quote
-
-        chain = qsession.get("sso_chain", [])
-        final = qsession.get("sso_final", account_url("/"))
-
-        if not g.get("user"):
-            qsession.pop("sso_chain", None)
-            qsession.pop("sso_final", None)
-            return redirect(final)
-
-        comeback = account_url("/auth/propagate")
-
-        while chain:
-            next_app = chain.pop(0)
-            qsession["sso_chain"] = chain
-
-            internal = (os.getenv(f"INTERNAL_URL_{next_app.upper()}") or f"http://{next_app}:8000").rstrip("/")
-            try:
-                async with aiohttp.ClientSession() as http:
-                    async with http.head(
-                        internal,
-                        timeout=aiohttp.ClientTimeout(total=2),
-                        allow_redirects=True,
-                    ) as resp:
-                        if resp.status < 500:
-                            login = app_url(next_app, f"/auth/login?next={quote(comeback, safe='')}")
-                            return redirect(login)
-            except Exception:
-                current_app.logger.warning("[propagate] skipping dead app: %s", next_app)
-                continue
-
-        qsession.pop("sso_chain", None)
-        qsession.pop("sso_final", None)
-        return redirect(final)
+        return redirect(redirect_url, 303)
 
     @auth_bp.post("/logout/")
     async def logout():