feat(KB-648): enable parallel test execution and optimize test performance

- Optimize backup tests using fake timers instead of real timeouts

- Enable parallel file execution in core, engine, CLI, and dashboard packages

- Add inline test helpers to reduce dependencies in dashboard routes tests

- Update executor tests with exact command matching and improved assertions

- Update AGENTS.md with test optimization patterns (fake timers, unique temp dirs)

packages/dashboard/tsconfig.json

@@ -6,6 +6,5 @@
     "jsx": "react-jsx",
     "types": ["node", "vitest/globals", "@testing-library/jest-dom"]
   },
-  "include": ["src/**/*"],
-  "exclude": ["src/**/*.test.ts", "src/**/*.test.tsx", "src/**/__tests__/**/*"]
+  "include": ["src/**/*"]
 }