test: clean temporary tool directories

[ken-jo]

Motivation

Seven reachable temporary-directory allocations in the Tools test area had no teardown contract. Three permission paths discarded the allocated root immediately, one persisted-permission test kept the root but never removed it, and three executable-resolution fixtures were not registered for cleanup. Repeated runs could therefore leave OS temporary directories behind.

Scope

• Preserve the executor and permission behavior under test while retaining each temporary root.
• Await cleanupTmpDir in finally after permission persistence and tool execution have settled.
• Register executable-resolution fixture directories immediately at creation and await their cleanup from afterEach after restoring process state.
• Keep existing behavior-under-test deletion semantics unchanged; no recursive rmSync teardown was added.

Impact and risk

This is test-only lifecycle hardening across three Tools test files. Runtime behavior and production contracts are unchanged. Risk is limited to teardown ordering; cleanup runs only after each test's resources and writes have completed.

Validation

• Focused Electron Vitest: 3 files passed, 138 passed / 6 skipped.
• Production typecheck passed.
• Test-typecheck baseline held: 295 files, 1517 existing errors; 6 files improved and 3 fully fixed.
• Duplicate-helper policy: 0 duplicate helper implementations.
• Source-text-safe policy passed.
• Pre-push test-only gate passed typecheck, typecheck gate self-test, baseline, duplicate policy, ABI check, and the same three targeted files.