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>

requirements.txt

@@ -13,7 +13,7 @@ patchright>=1.49.0
 python-dotenv~=1.0
 requests~=2.26
 beautifulsoup4~=4.12
-tf-playwright-stealth>=1.1.0
+playwright-stealth>=2.0.0
 xxhash~=3.4
 rank-bm25~=0.2
 colorama~=0.4