feat(FN-4012): restore workspace verification in chat room routes

The merge adds comprehensive test coverage for dashboard routing infrastructure — custom providers tests, setup routes tests, and chat manager tests — while making a minor adjustment to chat room route registration. The CLI side sees a small bundle output test update tied to the same FN-4012 work.

Fusion-Task-Id: FN-4012

packages/dashboard/src/routes/__tests__/custom-providers.test.ts

@@ -29,7 +29,11 @@ vi.mock("@fusion/core", async () => {
 
 vi.mock("@fusion/engine", () => ({
   createFnAgent: vi.fn(async () => ({ session: { state: { messages: [] }, prompt: vi.fn(), dispose: vi.fn() } })),
-  createResolvedAgentSession: vi.fn(async () => ({ session: { state: { messages: [] }, prompt: vi.fn(), dispose: vi.fn() } })),
+  createResolvedAgentSession: vi.fn(async () => ({
+    session: { state: { messages: [] }, prompt: vi.fn(), dispose: vi.fn() },
+    provider: "test",
+    model: "test",
+  })),
   promptWithFallback: vi.fn(),
 }));