fix: Replace tf-playwright-stealth with playwright-stealth dependency

Fixes #1553

The code imports from `playwright_stealth` module (e.g., StealthConfig,
stealth_async, stealth_sync with capital S) which is only available in
the `playwright-stealth` package, not `tf-playwright-stealth`.

Changed dependency from:
- tf-playwright-stealth>=1.1.0 (wrong package, exports lowercase names)
to:
- playwright-stealth>=2.0.0 (correct package, exports StealthConfig)

This fixes the mismatch between declared dependency and actual imports
in the codebase.

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

tests/check_dependencies.py

@@ -67,7 +67,7 @@ PACKAGE_MAPPINGS = {
     'patchright': 'patchright',
     'dotenv': 'python-dotenv',
     'fake_useragent': 'fake-useragent',
-    'playwright_stealth': 'tf-playwright-stealth',
+    'playwright_stealth': 'playwright-stealth',
     'sentence_transformers': 'sentence-transformers',
     'rank_bm25': 'rank-bm25',
     'snowballstemmer': 'snowballstemmer',