news: reduce headline max age from 24h to 12h, make configurable

- Added headline_max_age_seconds to NewsConfig (default 43200 = 12h)
- Replaced hardcoded 86400 in _fetch_news_sentiment_raw with config ref
- All downstream consumers (keyword scoring, LLM scoring, LLM summary,
  agent panel macro/contrarian) auto-filter through the same path

config.py

@@ -166,6 +166,9 @@ class NewsConfig:
     # Must stay below pre_event_buffer_minutes so an event can't cross
     # into the danger window while a stale cache says it's clear.
     context_cache_ttl_seconds: int = 600
+    # Maximum age of RSS headlines accepted for scoring. Older headlines
+    # are discarded before keyword analysis and LLM enrichment.
+    headline_max_age_seconds: int = 43200  # 12 hours
 
     rss_feeds: List[str] = field(default_factory=lambda: [
         "https://investinglive.com/feed/",

news_engine.py

@@ -770,8 +770,8 @@ class NewsEngine:
                         pub_date_el.text if pub_date_el is not None else None
                     )
 
-                    # Only recent headlines (last 24h)
+                    # Only recent headlines (configurable: headline_max_age_seconds)
-                    if pub_date and (datetime.now(timezone.utc) - pub_date).total_seconds() > 86400:
+                    if pub_date and (datetime.now(timezone.utc) - pub_date).total_seconds() > self.config.headline_max_age_seconds:
                         continue
 
                     # Dedup within and across feeds so a syndicated story