feat(x11): treatment-aware citation authority wired into research agents (#154)

The internal citation graph fed only RANKING (raw in-degree), and the per-citation
TREATMENT was never classified — so a precedent distinguished N times got the same
authority boost as one followed N times (INV-COR2 violation), and the signal never
reached the agents' reasoning. Wires the full path:

Phase 1 — scripts/classify_citation_treatments.py: classify each linked edge's
  treatment (followed/distinguished/…) from its match_context via
  corroboration.classify_treatment (Opus 4.8 @ xhigh, local), filling
  precedent_internal_citations.treatment. Idempotent.
Phase 2 — db.refresh_verified_layer: count only NON-negative treatments toward
  verified/cite_count (INV-COR2/COR4). Unclassified counts as neutral-positive so
  the signal degrades gracefully before classification runs.
Phase 3 — db.citation_authority(ids): per-precedent {total, positive, negative,
  unclassified, by_treatment}. Surfaced as `cited_by` in search_precedent_library
  hits and precedent_library_get, and `treatment` per incoming citation.
Phase 4 — legal-researcher/analyst/writer prompts: weigh & ARGUE authority
  ("הלכה שאומצה ב-N החלטות ועדת-ערר"), flag distinguished/overruled, never invent
  the count (INV-AH; writer is read-only of the analyst).

Auto-approval stays kill-switched off (chair gate preserved, INV-G10). No schema
change (treatment column already existed). Operational: run the classifier +
refresh_verified_layer over the 379 edges, then sync agents across companies.

Invariants: G2 (one classifier + one authority query, reused), INV-COR2/COR3/COR4
(negative never corroborates; point-specific; ≥N), INV-G10 (no auto-approval),
INV-AH (no invented numbers).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mcp-server/src/legal_mcp/tools/precedent_library.py

@@ -300,6 +300,20 @@ async def search_precedent_library(
         limit=limit,
         include_halachot=include_halachot,
     )
+    # X11 Phase 2 (#154): attach the incoming-citation authority breakdown so the
+    # research agent can WEIGH and ARGUE authority ("הלכה שאומצה ב-N החלטות ועדת-ערר")
+    # — and steer clear of a precedent that committees repeatedly distinguished /
+    # overruled. Batched: one query for the whole result page.
+    try:
+        ids = {str(r.get("case_law_id")) for r in results if r.get("case_law_id")}
+        if ids:
+            auth = await db.citation_authority([UUID(i) for i in ids])
+            for r in results:
+                cb = auth.get(str(r.get("case_law_id")))
+                if cb:
+                    r["cited_by"] = cb
+    except Exception:  # noqa: BLE001 — authority is an additive signal; never break search
+        pass
     elapsed_ms = int((time.perf_counter() - t0) * 1000)
     telemetry.log_search_bg(
         search_type="precedent_library",