refactor: dynamic UA matching, session reuse, score Optional, --output on all commands

- constants.py: sync_chrome_version() aligns UA/sec-ch-ua with impersonate target
- auth.py: reuse shared cffi session instead of creating duplicate
- filter.py: eliminate double weight building in score_tweet
- models.py: Tweet.score → Optional[float] for accurate display
- cli.py: add --output to search/likes/user-posts for consistency

uv.lock

@@ -950,7 +950,7 @@ wheels = [
 
 [[package]]
 name = "twitter-cli"
-version = "0.4.2"
+version = "0.4.3"
 source = { editable = "." }
 dependencies = [
     { name = "beautifulsoup4" },