fix(process-lock): fix test race condition in beforeEach

Root cause: Async cleanup in beforeEach was deleting testDir after
creating it, causing ENOENT errors. Fixed by removing async cleanup
from beforeEach and relying on:
- Unique directory names with hrtime for isolation
- Synchronous directory creation in beforeEach
- Async cleanup in afterEach
- Explicit cleanup before manual mkdir in individual tests

All 19 tests now pass locally.

Author: jdalton

test/process-lock.test.ts

@@ -17,7 +17,7 @@ describe('process-lock', () => {
   let testDir: string
   let lockPath: string
 
-  beforeEach(async () => {
+  beforeEach(() => {
     // Create unique test directory for each test.
     // Use process.hrtime.bigint() for higher precision than Date.now()
     testDir = path.join(
@@ -26,13 +26,6 @@ describe('process-lock', () => {
     )
     lockPath = path.join(testDir, 'test.lock')
 
-    // Clean up any existing test directory.
-    try {
-      await safeDelete(testDir, { force: true })
-    } catch {
-      // Ignore cleanup errors.
-    }
-
     // Ensure test directory exists.
     mkdirSync(testDir, { recursive: true })
   })