refactor: migrate monorepo from pnpm to Bun runtime and workspaces

- root: bun workspaces via package.json, packageManager bun@1.4.0, scripts use bun --filter
- backend: Bun.serve, bun test (vitest removed), bun --watch dev script, tsconfig types bun
- tests: migrate 6 test files from vitest to bun:test (mock.module)
- validate: replace @hono/zod-validator with hono validator + zod safeParse (fixes TS2589)
- lockfile: bunfig.toml saveTextLockfile, regenerated bun.lock (text) for turbo
- docs: AGENTS.md, README.md, stack.md updated to Bun stack

apps/backend/test/groups.test.ts

@@ -1,44 +1,27 @@
+import { beforeEach, describe, expect, it, mock, vi } from 'bun:test';
 import { Hono } from 'hono';
-import { beforeEach, describe, expect, it, vi } from 'vitest';
 
-const { db } = vi.hoisted(() => {
-  return {
-    db: {
-      group: {
-        findMany: vi.fn(),
-        findFirst: vi.fn(),
-        count: vi.fn(),
-        create: vi.fn(),
-      },
-      groupMember: {
-        create: vi.fn(),
-      },
-      organization: {
-        findUnique: vi.fn(),
-      },
-    } as {
-      group: {
-        findMany: ReturnType<typeof vi.fn>;
-        findFirst: ReturnType<typeof vi.fn>;
-        count: ReturnType<typeof vi.fn>;
-        create: ReturnType<typeof vi.fn>;
-      };
-      groupMember: { create: ReturnType<typeof vi.fn> };
-      organization: { findUnique: ReturnType<typeof vi.fn> };
-    },
-  };
-});
+const db = {
+  group: {
+    findMany: mock(),
+    findFirst: mock(),
+    count: mock(),
+    create: mock(),
+  },
+  groupMember: {
+    create: mock(),
+  },
+  organization: {
+    findUnique: mock(),
+  },
+};
 
-vi.mock('@/lib/prisma', () => ({
+mock.module('@/lib/prisma', () => ({
   default: db,
-  getPrismaClient: vi.fn(),
+  getPrismaClient: mock(),
   UnitOfWork: class {
-    executeResult = vi.fn(
-      async (cb: (tx: unknown) => Promise<unknown>) => cb(db),
-    );
-    execute = vi.fn(
-      async (cb: (tx: unknown) => Promise<unknown>) => cb(db),
-    );
+    executeResult = mock(async (cb: (tx: unknown) => Promise<unknown>) => cb(db));
+    execute = mock(async (cb: (tx: unknown) => Promise<unknown>) => cb(db));
   },
 }));
 
@@ -71,8 +54,8 @@ describe('groups routes', () => {
   });
 
   it('lists groups scoped to the current user', async () => {
-    vi.mocked(prisma.group.findMany).mockResolvedValue([group]);
-    vi.mocked(prisma.group.count).mockResolvedValue(1);
+    prisma.group.findMany.mockResolvedValue([group]);
+    prisma.group.count.mockResolvedValue(1);
 
     const res = await makeApp({ id: userId }).request('/groups');
 
@@ -118,9 +101,9 @@ describe('groups routes', () => {
       name: 'Escuela Alfa',
       members: [{ userId, role: 'owner' }],
     };
-    vi.mocked(prisma.organization.findUnique).mockResolvedValue(organization as never);
-    vi.mocked(prisma.group.findFirst).mockResolvedValue(null);
-    vi.mocked(prisma.group.create).mockResolvedValue(group);
+    prisma.organization.findUnique.mockResolvedValue(organization as never);
+    prisma.group.findFirst.mockResolvedValue(null);
+    prisma.group.create.mockResolvedValue(group);
 
     const res = await makeApp({ id: userId }).request('/groups/from-organization', {
       method: 'POST',
@@ -148,8 +131,8 @@ describe('groups routes', () => {
       name: 'Escuela Alfa',
       members: [{ userId, role: 'owner' }],
     };
-    vi.mocked(prisma.organization.findUnique).mockResolvedValue(organization as never);
-    vi.mocked(prisma.group.findFirst).mockResolvedValue(group);
+    prisma.organization.findUnique.mockResolvedValue(organization as never);
+    prisma.group.findFirst.mockResolvedValue(group);
 
     const res = await makeApp({ id: userId }).request('/groups/from-organization', {
       method: 'POST',
@@ -164,7 +147,7 @@ describe('groups routes', () => {
   });
 
   it('rejects creating a group for an unknown organization', async () => {
-    vi.mocked(prisma.organization.findUnique).mockResolvedValue(null);
+    prisma.organization.findUnique.mockResolvedValue(null);
 
     const res = await makeApp({ id: userId }).request('/groups/from-organization', {
       method: 'POST',
@@ -183,7 +166,7 @@ describe('groups routes', () => {
       name: 'Escuela Alfa',
       members: [{ userId: 'other-user', role: 'owner' }],
     };
-    vi.mocked(prisma.organization.findUnique).mockResolvedValue(organization as never);
+    prisma.organization.findUnique.mockResolvedValue(organization as never);
 
     const res = await makeApp({ id: userId }).request('/groups/from-organization', {
       method: 'POST',