feat(truthsocial): Add Truth Social as opt-in source

Mastodon-compatible API at truthsocial.com/api/v2/search.
Opt-in via TRUTHSOCIAL_TOKEN env var (bearer token from browser).
Silent when unconfigured. Full pipeline: search, parse, normalize,
score, dedupe, render across all 10 pipeline files.

27 new tests, 440 total passing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/lib/dedupe.py

@@ -234,6 +234,14 @@ def dedupe_bluesky(
     return dedupe_items(items, threshold)
 
 
+def dedupe_truthsocial(
+    items: List[schema.TruthSocialItem],
+    threshold: float = 0.7,
+) -> List[schema.TruthSocialItem]:
+    """Dedupe Truth Social items."""
+    return dedupe_items(items, threshold)
+
+
 def dedupe_polymarket(
     items: List[schema.PolymarketItem],
     threshold: float = 0.7,