Fixed the remaining Manager runtime coupling.

1. Root cause of the database error
The Manager proxy was bypassing installation checks, but / still resolved to src/app/page.tsx, which statically imported:
- @/auth
- Prisma
- business branding
- business permissions
- primary business data
The root route now redirects to /manager inside the proxy before the business homepage is evaluated.
2. Root cause of the Auth.js error
The global business SessionProvider was mounted around Manager pages. It automatically requested:

The business homepage is not evaluated first.
5. Provider and authentication separation
Manager mode:
- Uses ManagerProviders
- Uses the signed Manager cookie session
- Does not mount SessionProvider
- Does not call /api/auth/session
- Does not import business Auth.js or Prisma
Business mode:
- Dynamically loads the existing business Providers
- Continues using Auth.js and SessionProvider
- Preserves installation, /owner, and /staff behavior
6. Database independence
Manager mode now avoids database initialization for:
- Proxy requests
- Root metadata and viewport
- Root routing
- Manager pages
- Manager APIs
- Manifest requests
- Health requests
- Business Auth.js requests
- Business cron requests
No fake DATABASE_* variables were added.
7. Tests
Added coverage for:
- Manager / routing
- Manager /manager access
- No installation-state check in Manager mode
- Prisma import protection
- Business installation checks
- /owner protection
- Business Auth.js 404 boundary
- Manager health route without Prisma
- Manager manifest without business branding
8. Validation

src/app/api/cron/sync-google-reviews/route.ts

@@ -1,8 +1,5 @@
 import { NextResponse } from "next/server";
-import { prisma } from "@/lib/db/prisma";
-import { isInstalledForRequest } from "@/lib/installation/installation-state";
 import { secretsMatch } from "@/lib/security/secrets-match";
-import { syncGoogleReviewsForAllBusinesses } from "@/services/reviews/review-sync.service";
 
 /**
  * External trigger for the Google Reviews sync — mirrors
@@ -19,6 +16,8 @@ import { syncGoogleReviewsForAllBusinesses } from "@/services/reviews/review-syn
  * never duplicates anything.
  */
 export async function POST(request: Request) {
+  if (process.env.MANAGER_MODE === "true") return NextResponse.json({ error: "Not available on Manager." }, { status: 404 });
+
   const secret = process.env.CRON_SECRET;
   if (!secret) {
     return NextResponse.json({ error: "CRON_SECRET is not configured on this deployment." }, { status: 503 });
@@ -29,10 +28,15 @@ export async function POST(request: Request) {
     return NextResponse.json({ error: "Unauthorized." }, { status: 401 });
   }
 
+  const { isInstalledForRequest } = await import("@/lib/installation/installation-state");
   if (!(await isInstalledForRequest())) {
     return NextResponse.json({ skipped: "not_installed" });
   }
 
+  const [{ prisma }, { syncGoogleReviewsForAllBusinesses }] = await Promise.all([
+    import("@/lib/db/prisma"),
+    import("@/services/reviews/review-sync.service"),
+  ]);
   const results = await syncGoogleReviewsForAllBusinesses(prisma);
   return NextResponse.json({ results });
 }