refactor: align display label and docs with sentiment_analyst rename

The agent ingests news, StockTwits, and Reddit, but CLI labels, the
README description, and the legacy shim docstring still framed it as
social-media-only. Updates all user-visible surfaces so the name and
the implementation match.

cli/utils.py

@@ -16,7 +16,7 @@ TICKER_INPUT_EXAMPLES = "Examples: SPY, CNC.TO, 7203.T, 0700.HK"
 
 ANALYST_ORDER = [
     ("Market Analyst", AnalystType.MARKET),
-    ("Social Media Analyst", AnalystType.SOCIAL),
+    ("Sentiment Analyst", AnalystType.SOCIAL),
     ("News Analyst", AnalystType.NEWS),
     ("Fundamentals Analyst", AnalystType.FUNDAMENTALS),
 ]