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>

pyproject.toml

@@ -26,7 +26,7 @@ dependencies = [
     "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",
     "snowballstemmer~=2.2",