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

docs/skipped-test-inventory.md

@@ -78,7 +78,7 @@ Previously tracked actionable skip follow-ups are now resolved and should not be
 
 - **FN-2085**: wildcard proxy POST body forwarding coverage is active.
 - **FN-2076 / FN-2106 / FN-2109**: NewAgentDialog and MissionInterviewModal rollback favorite-toggle regressions are active interaction tests.
-- The former engine `executor.test.ts` step-session alias skip is no longer present; ownership now lives in active engine tests.
+- The former single-file executor step-session alias skip is no longer present; ownership now lives in the split executor suites (`executor-*.test.ts`).
 
 Searches for those IDs in repository test code and docs now return no active TODO/skip markers tied to unresolved work.
 

docs/test-audit-report.md

@@ -117,7 +117,7 @@ _Date: 2026-04-08_
 
 Sampled files (2-3 per package):
 - Core: `store.test.ts`, `db-migrate.test.ts`, `central-core.test.ts`
-- Engine: `executor.test.ts`, `stuck-task-detector.test.ts`
+- Engine: `executor-core.test.ts`, `executor-step-session.test.ts`, `stuck-task-detector.test.ts`
 - CLI: `commands/task.test.ts`, `commands/dashboard.test.ts`
 - Dashboard: `routes.test.ts`, `SettingsModal.test.tsx`, `components/__tests__/Column.test.tsx`