feat(FN-3720): split executor.test.ts into eight focused suites and add she

The merge splits the large monolithic `executor.test.ts` into seven focused test suites covering core logic, pause behavior, prompt handling, recovery, review verdicts, step sessions, and worktree operations, and adds shell context hook plumbing across the dashboard, desktop, and mobile packages to

Fusion-Task-Id: FN-3720

packages/engine/package.json

@@ -31,8 +31,8 @@
     "build": "tsc",
     "typecheck": "tsc --noEmit",
     "test": "vitest run --silent=passed-only --reporter=dot",
-    "test:executor": "vitest run src/executor.test.ts",
-    "test:watch": "vitest src/executor.test.ts --watch"
+    "test:executor": "vitest run src/__tests__/executor-*.test.ts",
+    "test:watch": "vitest src/__tests__/executor-*.test.ts --watch"
   },
   "dependencies": {
     "@fusion/core": "workspace:*",