fix(test): ensure clean state in beforeEach for process-lock tests

Add cleanup in beforeEach to prevent test isolation issues. Tests were failing
in CI due to leftover lock directories from previous tests causing EEXIST errors.

Author: jdalton

test/process-lock.test.ts

@@ -17,14 +17,21 @@ describe('process-lock', () => {
   let testDir: string
   let lockPath: string
 
-  beforeEach(() => {
+  beforeEach(async () => {
     // Create unique test directory for each test.
     testDir = path.join(
       tmpdir(),
       `process-lock-test-${Date.now()}-${Math.random().toString(36).slice(2)}`,
     )
     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 })
   })