feat: add comprehensive integration tests for auto-mode-service

- Created git-test-repo helper for managing test git repositories
- Added 13 integration tests covering:
  - Worktree operations (create, error handling, non-worktree mode)
  - Feature execution (status updates, model selection, duplicate prevention)
  - Auto loop (start/stop, pending features, max concurrency, events)
  - Error handling (provider errors, continue after failures)
- Integration tests use real git operations with temporary repos
- All 416 tests passing with 72.65% overall coverage
- Service coverage improved: agent-service 58%, auto-mode-service 44%, feature-loader 66%

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

apps/server/tests/setup.ts

@@ -0,0 +1,16 @@
+/**
+ * Vitest global setup file
+ * Runs before each test file
+ */
+
+import { vi, beforeEach } from "vitest";
+
+// Set test environment variables
+process.env.NODE_ENV = "test";
+process.env.DATA_DIR = "/tmp/test-data";
+process.env.ALLOWED_PROJECT_DIRS = "/tmp/test-projects";
+
+// Reset all mocks before each test
+beforeEach(() => {
+  vi.clearAllMocks();
+});