Fix flaky upload_skill tests by restoring cwd in parallel scraping tests

Problem:
- 2 tests in test_upload_skill.py failing intermittently in CI
- Tests passed individually but failed when run after test_parallel_scraping.py
- Tests failed with exit code 2 instead of 0 when running `--help`

Root Cause:
- test_parallel_scraping.py calls `os.chdir(tmpdir)` to create temporary test directories
- These directory changes persisted across test classes
- When upload_skill CLI tests ran subprocess with path 'cli/upload_skill.py',
  the relative path was broken because cwd was still in the temp directory
- Result: subprocess couldn't find the script, returned exit code 2

Fix:
- Added setUp/tearDown to all 6 test classes in test_parallel_scraping.py
- setUp saves original cwd with `self.original_cwd = os.getcwd()`
- tearDown restores it with `os.chdir(self.original_cwd)`
- Ensures tests don't pollute working directory state for subsequent tests

Impact:
- All 158 tests now pass consistently
- No more flaky failures in CI
- Test isolation properly maintained

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/test_parallel_scraping.py

@@ -22,6 +22,14 @@ from doc_scraper import DocToSkillConverter
 class TestParallelScrapingConfiguration(unittest.TestCase):
     """Test parallel scraping configuration and initialization"""
 
+    def setUp(self):
+        """Save original working directory"""
+        self.original_cwd = os.getcwd()
+
+    def tearDown(self):
+        """Restore original working directory"""
+        os.chdir(self.original_cwd)
+
     def test_single_worker_default(self):
         """Test default is single-worker mode"""
         config = {
@@ -71,6 +79,14 @@ class TestParallelScrapingConfiguration(unittest.TestCase):
 class TestUnlimitedMode(unittest.TestCase):
     """Test unlimited scraping mode"""
 
+    def setUp(self):
+        """Save original working directory"""
+        self.original_cwd = os.getcwd()
+
+    def tearDown(self):
+        """Restore original working directory"""
+        os.chdir(self.original_cwd)
+
     def test_unlimited_with_none(self):
         """Test max_pages: None enables unlimited mode"""
         config = {
@@ -118,6 +134,14 @@ class TestUnlimitedMode(unittest.TestCase):
 class TestRateLimiting(unittest.TestCase):
     """Test rate limiting configuration"""
 
+    def setUp(self):
+        """Save original working directory"""
+        self.original_cwd = os.getcwd()
+
+    def tearDown(self):
+        """Restore original working directory"""
+        os.chdir(self.original_cwd)
+
     def test_rate_limit_from_config(self):
         """Test rate_limit is read from config"""
         config = {
@@ -163,6 +187,14 @@ class TestRateLimiting(unittest.TestCase):
 class TestThreadSafety(unittest.TestCase):
     """Test thread-safety fixes"""
 
+    def setUp(self):
+        """Save original working directory"""
+        self.original_cwd = os.getcwd()
+
+    def tearDown(self):
+        """Restore original working directory"""
+        os.chdir(self.original_cwd)
+
     def test_lock_protects_visited_urls(self):
         """Test visited_urls operations are protected by lock"""
         config = {
@@ -201,6 +233,14 @@ class TestThreadSafety(unittest.TestCase):
 class TestScrapingModes(unittest.TestCase):
     """Test different scraping mode combinations"""
 
+    def setUp(self):
+        """Save original working directory"""
+        self.original_cwd = os.getcwd()
+
+    def tearDown(self):
+        """Restore original working directory"""
+        os.chdir(self.original_cwd)
+
     def test_single_threaded_limited(self):
         """Test traditional single-threaded limited mode"""
         config = {
@@ -272,6 +312,14 @@ class TestScrapingModes(unittest.TestCase):
 class TestDryRunWithNewFeatures(unittest.TestCase):
     """Test dry-run mode works with new features"""
 
+    def setUp(self):
+        """Save original working directory"""
+        self.original_cwd = os.getcwd()
+
+    def tearDown(self):
+        """Restore original working directory"""
+        os.chdir(self.original_cwd)
+
     def test_dry_run_with_parallel(self):
         """Test dry-run with parallel workers"""
         config = {