fix(gateway): scope /api/teams endpoints to team membership (#1428)

Every teams route sat behind AuthGuard only: any authenticated user
could enumerate all teams and their full member records (webUI audit
A3 F9.2, upgraded to major in cross-review).

- GET /api/teams: members see only their teams (new
  TeamsService.findAllForUser, same two-step pattern as
  brain/projects.findAllForUser); admins keep the full list.
- GET :teamId, :teamId/members: require admin or membership; 404 for a
  missing team, 403 for no access — the projects-controller convention.
- GET :teamId/members/:userId: self-lookup stays open; looking up
  another user is team-scoped like the rest.

No consumers of /api/teams exist in the monorepo, so no caller changes.
New controller spec: 9 tests. Gateway suite 818 passed, typecheck clean.

apps/gateway/src/workspace/teams.controller.spec.ts

@@ -0,0 +1,123 @@
+import 'reflect-metadata';
+import { type CanActivate, type ExecutionContext, type INestApplication } from '@nestjs/common';
+import { FastifyAdapter, type NestFastifyApplication } from '@nestjs/platform-fastify';
+import { Test } from '@nestjs/testing';
+import request from 'supertest';
+import { afterAll, beforeAll, beforeEach, describe, expect, it, vi } from 'vitest';
+import { AuthGuard } from '../auth/auth.guard.js';
+import { TeamsController } from './teams.controller.js';
+import { TeamsService } from './teams.service.js';
+
+const teamAlpha = { id: 'team-alpha', name: 'Alpha' };
+const teamBeta = { id: 'team-beta', name: 'Beta' };
+
+// user-1 is a member of team-alpha only; admin-1 has role admin.
+let currentUser: { id: string; role?: string } = { id: 'user-1' };
+
+const teamsServiceMock = {
+  findAll: vi.fn(() => Promise.resolve([teamAlpha, teamBeta])),
+  findAllForUser: vi.fn((userId: string) =>
+    Promise.resolve(userId === 'user-1' ? [teamAlpha] : []),
+  ),
+  findById: vi.fn((id: string) => Promise.resolve([teamAlpha, teamBeta].find((t) => t.id === id))),
+  listMembers: vi.fn(() => Promise.resolve([{ teamId: 'team-alpha', userId: 'user-1' }])),
+  isMember: vi.fn((teamId: string, userId: string) =>
+    Promise.resolve(teamId === 'team-alpha' && userId === 'user-1'),
+  ),
+};
+
+const authGuard: CanActivate = {
+  canActivate(context: ExecutionContext): boolean {
+    const requestContext = context
+      .switchToHttp()
+      .getRequest<{ user?: { id: string; role?: string } }>();
+    requestContext.user = currentUser;
+    return true;
+  },
+};
+
+describe('teams endpoints are scoped to membership', () => {
+  let app: INestApplication;
+
+  beforeAll(async () => {
+    const moduleRef = await Test.createTestingModule({
+      controllers: [TeamsController],
+      providers: [{ provide: TeamsService, useValue: teamsServiceMock }],
+    })
+      .overrideGuard(AuthGuard)
+      .useValue(authGuard)
+      .compile();
+
+    app = moduleRef.createNestApplication<NestFastifyApplication>(new FastifyAdapter());
+    await app.init();
+    await app.getHttpAdapter().getInstance().ready();
+  });
+
+  beforeEach(() => {
+    currentUser = { id: 'user-1' };
+    vi.clearAllMocks();
+  });
+
+  afterAll(async () => {
+    await app.close();
+  });
+
+  it('GET /api/teams returns only the teams the user belongs to', async () => {
+    const response = await request(app.getHttpServer()).get('/api/teams');
+    expect(response.status).toBe(200);
+    expect(response.body).toEqual([teamAlpha]);
+    expect(teamsServiceMock.findAll).not.toHaveBeenCalled();
+  });
+
+  it('GET /api/teams returns every team for an admin', async () => {
+    currentUser = { id: 'admin-1', role: 'admin' };
+    const response = await request(app.getHttpServer()).get('/api/teams');
+    expect(response.status).toBe(200);
+    expect(response.body).toEqual([teamAlpha, teamBeta]);
+    expect(teamsServiceMock.findAllForUser).not.toHaveBeenCalled();
+  });
+
+  it('GET /api/teams/:teamId returns 403 for a non-member', async () => {
+    const response = await request(app.getHttpServer()).get('/api/teams/team-beta');
+    expect(response.status).toBe(403);
+  });
+
+  it('GET /api/teams/:teamId returns 404 for a missing team', async () => {
+    const response = await request(app.getHttpServer()).get('/api/teams/team-missing');
+    expect(response.status).toBe(404);
+  });
+
+  it('GET /api/teams/:teamId returns the team for a member', async () => {
+    const response = await request(app.getHttpServer()).get('/api/teams/team-alpha');
+    expect(response.status).toBe(200);
+    expect(response.body).toEqual(teamAlpha);
+  });
+
+  it('GET /api/teams/:teamId/members returns 403 for a non-member and members for a member', async () => {
+    const denied = await request(app.getHttpServer()).get('/api/teams/team-beta/members');
+    expect(denied.status).toBe(403);
+    expect(teamsServiceMock.listMembers).not.toHaveBeenCalled();
+
+    const allowed = await request(app.getHttpServer()).get('/api/teams/team-alpha/members');
+    expect(allowed.status).toBe(200);
+    expect(allowed.body).toEqual([{ teamId: 'team-alpha', userId: 'user-1' }]);
+  });
+
+  it('GET /api/teams/:teamId/members/:userId allows a self-lookup on any team', async () => {
+    const response = await request(app.getHttpServer()).get('/api/teams/team-beta/members/user-1');
+    expect(response.status).toBe(200);
+    expect(response.body).toEqual({ isMember: false });
+  });
+
+  it('GET /api/teams/:teamId/members/:userId denies looking up another user on a foreign team', async () => {
+    const response = await request(app.getHttpServer()).get('/api/teams/team-beta/members/user-2');
+    expect(response.status).toBe(403);
+  });
+
+  it('an admin can look up any membership', async () => {
+    currentUser = { id: 'admin-1', role: 'admin' };
+    const response = await request(app.getHttpServer()).get('/api/teams/team-alpha/members/user-1');
+    expect(response.status).toBe(200);
+    expect(response.body).toEqual({ isMember: true });
+  });
+});

apps/gateway/src/workspace/teams.controller.ts

@@ -1,30 +1,68 @@
-import { Controller, Get, Param, UseGuards } from '@nestjs/common';
+import {
+  Controller,
+  ForbiddenException,
+  Get,
+  NotFoundException,
+  Param,
+  UseGuards,
+} from '@nestjs/common';
 import { AuthGuard } from '../auth/auth.guard.js';
+import { CurrentUser } from '../auth/current-user.decorator.js';
 import { TeamsService } from './teams.service.js';
 
+type RequestUser = { id: string; role?: string };
+
 @Controller('api/teams')
 @UseGuards(AuthGuard)
 export class TeamsController {
   constructor(private readonly teams: TeamsService) {}
 
   @Get()
-  async list() {
-    return this.teams.findAll();
+  async list(@CurrentUser() user: RequestUser) {
+    if (user.role === 'admin') {
+      return this.teams.findAll();
+    }
+    return this.teams.findAllForUser(user.id);
   }
 
   @Get(':teamId')
-  async findOne(@Param('teamId') teamId: string) {
-    return this.teams.findById(teamId);
+  async findOne(@Param('teamId') teamId: string, @CurrentUser() user: RequestUser) {
+    return this.getAccessibleTeam(teamId, user);
   }
 
   @Get(':teamId/members')
-  async listMembers(@Param('teamId') teamId: string) {
+  async listMembers(@Param('teamId') teamId: string, @CurrentUser() user: RequestUser) {
+    await this.getAccessibleTeam(teamId, user);
     return this.teams.listMembers(teamId);
   }
 
   @Get(':teamId/members/:userId')
-  async checkMembership(@Param('teamId') teamId: string, @Param('userId') userId: string) {
+  async checkMembership(
+    @Param('teamId') teamId: string,
+    @Param('userId') userId: string,
+    @CurrentUser() user: RequestUser,
+  ) {
+    // A user may always ask about their own membership; anything else is
+    // team-scoped like the other routes.
+    if (userId !== user.id) {
+      await this.getAccessibleTeam(teamId, user);
+    }
     const isMember = await this.teams.isMember(teamId, userId);
     return { isMember };
   }
+
+  /**
+   * Team-scoped access: admins see any team; everyone else only teams they
+   * are a member of. NotFoundException when the team does not exist and
+   * ForbiddenException when the user lacks access (same convention as the
+   * projects controller).
+   */
+  private async getAccessibleTeam(teamId: string, user: RequestUser) {
+    const team = await this.teams.findById(teamId);
+    if (!team) throw new NotFoundException('Team not found');
+    if (user.role === 'admin') return team;
+    const isMember = await this.teams.isMember(teamId, user.id);
+    if (!isMember) throw new ForbiddenException('Not a member of this team');
+    return team;
+  }
 }

apps/gateway/src/workspace/teams.service.ts

@@ -1,5 +1,5 @@
 import { Inject, Injectable, Logger } from '@nestjs/common';
-import { eq, and, type Db, teams, teamMembers, projects } from '@mosaicstack/db';
+import { eq, and, inArray, type Db, teams, teamMembers, projects } from '@mosaicstack/db';
 import { DB } from '../database/database.module.js';
 
 @Injectable()
@@ -56,6 +56,21 @@ export class TeamsService {
     return this.db.select().from(teams);
   }
 
+  /**
+   * List only the teams the user is a member of.
+   */
+  async findAllForUser(userId: string) {
+    const memberRows = await this.db
+      .select({ teamId: teamMembers.teamId })
+      .from(teamMembers)
+      .where(eq(teamMembers.userId, userId));
+
+    const teamIds = memberRows.map((r) => r.teamId);
+    if (teamIds.length === 0) return [];
+
+    return this.db.select().from(teams).where(inArray(teams.id, teamIds));
+  }
+
   /**
    * Find a team by ID.
    */