fix(api,web): separate workspace context from auth session (#551)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/api/src/workspaces/workspaces.controller.spec.ts

@@ -0,0 +1,75 @@
+import { describe, it, expect, beforeEach, vi } from "vitest";
+import { Test, TestingModule } from "@nestjs/testing";
+import { WorkspacesController } from "./workspaces.controller";
+import { WorkspacesService } from "./workspaces.service";
+import { AuthGuard } from "../auth/guards/auth.guard";
+import { WorkspaceMemberRole } from "@prisma/client";
+import type { AuthUser } from "@mosaic/shared";
+
+describe("WorkspacesController", () => {
+  let controller: WorkspacesController;
+  let service: WorkspacesService;
+
+  const mockWorkspacesService = {
+    getUserWorkspaces: vi.fn(),
+  };
+
+  const mockUser: AuthUser = {
+    id: "user-1",
+    email: "test@example.com",
+    name: "Test User",
+  };
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      controllers: [WorkspacesController],
+      providers: [
+        {
+          provide: WorkspacesService,
+          useValue: mockWorkspacesService,
+        },
+      ],
+    })
+      .overrideGuard(AuthGuard)
+      .useValue({ canActivate: () => true })
+      .compile();
+
+    controller = module.get<WorkspacesController>(WorkspacesController);
+    service = module.get<WorkspacesService>(WorkspacesService);
+
+    vi.clearAllMocks();
+  });
+
+  describe("GET /api/workspaces", () => {
+    it("should call service with authenticated user id", async () => {
+      mockWorkspacesService.getUserWorkspaces.mockResolvedValueOnce([]);
+
+      await controller.getUserWorkspaces(mockUser);
+
+      expect(service.getUserWorkspaces).toHaveBeenCalledWith("user-1");
+    });
+
+    it("should return workspace list from service", async () => {
+      const mockWorkspaces = [
+        {
+          id: "ws-1",
+          name: "My Workspace",
+          ownerId: "user-1",
+          role: WorkspaceMemberRole.OWNER,
+          createdAt: new Date("2026-01-01"),
+        },
+      ];
+      mockWorkspacesService.getUserWorkspaces.mockResolvedValueOnce(mockWorkspaces);
+
+      const result = await controller.getUserWorkspaces(mockUser);
+
+      expect(result).toEqual(mockWorkspaces);
+    });
+
+    it("should propagate service errors", async () => {
+      mockWorkspacesService.getUserWorkspaces.mockRejectedValueOnce(new Error("Database error"));
+
+      await expect(controller.getUserWorkspaces(mockUser)).rejects.toThrow("Database error");
+    });
+  });
+});