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/fixtures/configs.ts

@@ -0,0 +1,25 @@
+/**
+ * Configuration fixtures for testing Codex config manager
+ */
+
+export const tomlConfigFixture = `
+experimental_use_rmcp_client = true
+
+[mcp_servers.automaker-tools]
+command = "node"
+args = ["/path/to/server.js"]
+startup_timeout_sec = 10
+tool_timeout_sec = 60
+enabled_tools = ["UpdateFeatureStatus"]
+
+[mcp_servers.automaker-tools.env]
+AUTOMAKER_PROJECT_PATH = "/path/to/project"
+`;
+
+export const codexAuthJsonFixture = {
+  token: {
+    access_token: "test-access-token",
+    refresh_token: "test-refresh-token",
+    id_token: "test-id-token",
+  },
+};