ActivityPods Solid-OIDC auth flow in AuthGate with pod provider picker and /login callback

src/index.ts

@@ -63,13 +63,22 @@ const server = serve({
     // (both serve from src/, so they miss build.ts's compile-time `define`). The app
     // entry (frontend.tsx) fetches this before it loads the app tree, so
     // `sharedWallet.ts` sees the password. Empty env → '' → no shared wallet.
-    "/festipod-config.json": () =>
-      Response.json({
+    "/festipod-config.json": () => {
+      const backendUrl = process.env.VITE_BACKEND_URL?.trim() ?? "";
+      const backendClientId = process.env.VITE_BACKEND_CLIENT_ID?.trim() ?? "";
+      return Response.json({
         sharedWalletPassword: process.env.FESTIPOD_SHARED_WALLET_PASSWORD ?? "",
         // Auto-seed gate (OFF by default): only set when the env var is present, so
         // the front seeds an empty wallet only on explicit opt-in (see autoSeed.ts).
         autoSeed: process.env.FESTIPOD_AUTO_SEED ?? "",
-      }),
+        // ActivityPods backend coupling: the frontend needs the backend URL and the
+        // Solid-OIDC client_id (defaults to the app description document served by
+        // the backend). The Pod provider URL is optional; empty → user picks one.
+        backendUrl,
+        backendClientId,
+        podProviderUrl: process.env.VITE_POD_PROVIDER_URL?.trim() ?? "",
+      });
+    },
 
     // The shared wallet file — the `fileUrl` the app hands the SDK, when configured.
     //