fix: add x-client-transaction-id header for search API

- Root cause: Twitter's SearchTimeline endpoint requires x-client-transaction-id
  header that HomeTimeline/Bookmarks don't enforce
- Integrate XClientTransaction library for header generation
- Add requests + beautifulsoup4 dependencies
- Fix SearchTimeline variables (override base timeline vars)
- Update FEATURES dict and fallback queryIds to match live x.com values

pyproject.toml

@@ -30,6 +30,8 @@ dependencies = [
     "click>=8.0",
     "rich>=13.0",
     "PyYAML>=6.0",
+    "xclienttransaction>=1.0.1",
+    "requests>=2.32.4",
 ]
 
 [project.optional-dependencies]