feat(principles): retroactive cull (Phase C) + source-derived terminology (Phase D, #152)

Phase C — scripts/cull_principles.py: re-adjudicates every existing 'original'
principle with the SAME panel regime (panel_keep_score → classify → apply_cap),
reversible (CSV backup + rejected canonical recoverable), usage-throttled.
panel_extraction.panel_keep_score + apply_cap (shared, G2). Dry-run on 3
decisions: 37→15 survive.

Phase D — services/principles.py: source-derived label הלכה (binding court) /
כלל פרשני (committee) / עיקרון (persuasive); umbrella עקרונות משפטיים. Wired into
canonical_halacha_get/list (principle_class+principle_label). UI string changes
deferred to the Claude Design gate. spec INV-LRN7; SCRIPTS.md; 7 new tests; 428 green.

Phase E needs no new code — synthesis already targets pending_synthesis, which the
cull leaves only on survivors (rejected canonicals → 'rejected').

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

scripts/cull_principles.py

@@ -0,0 +1,204 @@
+#!/usr/bin/env python3
+"""Retroactive cull of the legal-principles corpus via the 3-model panel (#152, Phase C).
+
+The corpus grew to ~5,243 principles (18.8/decision) under the old single-model
+auto-approve. This re-adjudicates EVERY existing 'original' principle with the
+SAME regime the extractor now uses going forward (chaim 2026-06-19):
+
+  • 3 judges (Claude local + DeepSeek + Gemini) vote keep + score on each principle.
+  • Approval rule: 3 votes→survive · 2 & score≥0.85→survive · 2 & <0.85→chair
+    (pending_review) · ≤1→reject.
+  • Per DECISION, survivors are capped to HALACHA_PANEL_MAX_NEW (=5) by score; the
+    rest are rejected (over-cap).
+
+All logic is shared with the extractor via services/panel_extraction (G2). The
+cull is REVERSIBLE: a CSV backup of every (id, old_status) is written before any
+write, and a rejected principle's canonical is also set 'rejected' (recoverable).
+Throttled by usage_limits (stops gracefully at the soft ceiling, resumable).
+
+  cd ~/legal-ai/mcp-server
+  HOME=/home/chaim .venv/bin/python ../scripts/cull_principles.py --sample 5     # dry-run, 5 decisions
+  HOME=/home/chaim .venv/bin/python ../scripts/cull_principles.py --dry-run      # all, dry-run
+  HOME=/home/chaim .venv/bin/python ../scripts/cull_principles.py --apply        # full, throttled
+"""
+from __future__ import annotations
+
+import argparse
+import asyncio
+import csv
+import os
+import random
+import sys
+from collections import Counter
+from datetime import datetime, timezone
+from uuid import UUID
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "mcp-server", "src"))
+
+from legal_mcp import config  # noqa: E402
+from legal_mcp.services import db, panel_extraction as pe  # noqa: E402
+
+try:
+    from legal_mcp.services import usage_limits
+except Exception:  # pragma: no cover
+    usage_limits = None
+
+AUDIT_DIR = os.path.join(os.path.dirname(__file__), "..", "data", "audit")
+_JUDGE_CONCURRENCY = 4
+
+
+async def _decisions(limit, sample):
+    """case_law ids that have 'original' principles, with source metadata."""
+    pool = await db.get_pool()
+    rows = await pool.fetch(
+        "SELECT cl.id, cl.case_number, cl.source_kind, cl.is_binding, "
+        "       count(*) AS n "
+        "FROM halachot h JOIN case_law cl ON cl.id = h.case_law_id "
+        "WHERE h.instance_type = 'original' AND h.review_status <> 'rejected' "
+        "GROUP BY cl.id, cl.case_number, cl.source_kind, cl.is_binding "
+        "ORDER BY n DESC",
+    )
+    items = [dict(r) for r in rows]
+    if sample and sample < len(items):
+        items = random.sample(items, sample)
+    if limit:
+        items = items[:limit]
+    return items
+
+
+async def _principles(case_law_id):
+    pool = await db.get_pool()
+    rows = await pool.fetch(
+        "SELECT id, rule_statement, supporting_quote, reasoning_summary, "
+        "       canonical_id, review_status "
+        "FROM halachot WHERE case_law_id = $1 AND instance_type = 'original' "
+        "AND review_status <> 'rejected' ORDER BY halacha_index",
+        case_law_id,
+    )
+    return [dict(r) for r in rows]
+
+
+def _throttled():
+    if usage_limits is None:
+        return False, "no usage_limits"
+    u = usage_limits.subscription_usage()
+    if u is None:
+        return False, "usage read failed"
+    over, _r, detail = usage_limits.ceiling_status(u)
+    return over, detail
+
+
+async def _judge_decision(dec, sem):
+    principles = await _principles(dec["id"])
+    if not principles:
+        return []
+
+    async def one(p):
+        async with sem:
+            v = await pe.panel_keep_score(
+                p["rule_statement"], p["supporting_quote"], p.get("reasoning_summary") or "",
+                source_kind=dec["source_kind"] or "external_upload",
+                is_binding=bool(dec["is_binding"]),
+            )
+        return {**p, **v}
+
+    judged = await asyncio.gather(*[one(p) for p in principles])
+    return pe.apply_cap(list(judged))
+
+
+async def _apply_decision(judged, reviewer):
+    pool = await db.get_pool()
+    async with pool.acquire() as conn:
+        async with conn.transaction():
+            for j in judged:
+                fv = j["final_verdict"]
+                if fv == "approved":
+                    await conn.execute(
+                        "UPDATE halachot SET review_status='approved', reviewed_at=now(), "
+                        "reviewer=$2, updated_at=now() WHERE id=$1", j["id"], reviewer)
+                elif fv == "pending_review":
+                    await conn.execute(
+                        "UPDATE halachot SET review_status='pending_review', reviewer=$2, "
+                        "updated_at=now() WHERE id=$1", j["id"], reviewer)
+                else:  # rejected — also reject its canonical (reversible)
+                    await conn.execute(
+                        "UPDATE halachot SET review_status='rejected', reviewed_at=now(), "
+                        "reviewer=$2, updated_at=now() WHERE id=$1", j["id"], reviewer)
+                    if j.get("canonical_id"):
+                        await conn.execute(
+                            "UPDATE canonical_halachot SET review_status='rejected', "
+                            "updated_at=now() WHERE id=$1", j["canonical_id"])
+
+
+async def _run(apply, limit, sample, throttle, verbose):
+    decisions = await _decisions(limit, sample)
+    mode = "APPLY" if apply else "DRY-RUN"
+    print(f"[{mode}] {len(decisions)} decisions with principles "
+          f"(throttle={'on' if throttle else 'off'})\n", flush=True)
+    if not decisions:
+        print("nothing to do.")
+        return 0
+
+    stamp = datetime.now(timezone.utc).strftime("%Y%m%dT%H%M%SZ")
+    os.makedirs(AUDIT_DIR, exist_ok=True)
+    audit = os.path.join(AUDIT_DIR, f"principle-cull-{'apply' if apply else 'dryrun'}-{stamp}.csv")
+    reviewer = f"cull:panel v{config.HALACHA_PANEL_SCORE_FLOOR} cap{config.HALACHA_PANEL_MAX_NEW}"
+    sem = asyncio.Semaphore(_JUDGE_CONCURRENCY)
+    tally = Counter()
+    n_in = n_out = 0
+    stopped = False
+
+    with open(audit, "w", newline="", encoding="utf-8") as fh:
+        w = csv.writer(fh)
+        w.writerow(["case_number", "halacha_id", "old_status", "final_verdict",
+                    "votes", "score", "canonical_id", "rule"])
+        for k, dec in enumerate(decisions, 1):
+            if throttle:
+                over, detail = _throttled()
+                if over:
+                    print(f"\n⏸  usage ceiling ({detail}) — stopping at {k-1}/{len(decisions)}. "
+                          f"Re-run to resume.", flush=True)
+                    stopped = True
+                    break
+            judged = await _judge_decision(dec, sem)
+            survivors = sum(1 for j in judged if j["final_verdict"] in ("approved", "pending_review"))
+            n_in += len(judged)
+            n_out += survivors
+            for j in judged:
+                tally[j["final_verdict"]] += 1
+                w.writerow([dec["case_number"], str(j["id"]), j["review_status"],
+                            j["final_verdict"], j["votes"], j["score"],
+                            str(j.get("canonical_id") or ""), (j["rule_statement"] or "")[:160]])
+            if apply and judged:
+                await _apply_decision(judged, reviewer)
+            print(f"[{k}/{len(decisions)}] {dec['case_number']:<16} "
+                  f"{len(judged)}→{survivors} survive", flush=True)
+            if verbose:
+                for j in judged:
+                    mark = {"approved": "✓", "pending_review": "→chair", "rejected": "✗"}[j["final_verdict"]]
+                    print(f"      {mark} v={j['votes']} s={j['score']} {(j['rule_statement'] or '')[:80]}")
+
+    print(f"\n── {mode} summary{' (stopped early)' if stopped else ''} ──")
+    print(f"   principles judged: {n_in} → survive: {n_out}  ({n_in - n_out} rejected)")
+    for v, c in tally.most_common():
+        print(f"   {v:<16} {c}")
+    print(f"\naudit CSV: {audit}")
+    if not apply:
+        print("dry-run — no DB writes. Re-run with --apply to commit (reversible).")
+    return 0
+
+
+def main():
+    p = argparse.ArgumentParser(description="Retroactive principle cull via 3-model panel (#152)")
+    p.add_argument("--apply", action="store_true", help="write verdicts (reversible, CSV-backed)")
+    p.add_argument("--dry-run", action="store_true", help="explicit dry-run (default)")
+    p.add_argument("--limit", type=int, default=None)
+    p.add_argument("--sample", type=int, default=None, help="random sample of N decisions")
+    p.add_argument("--no-throttle", action="store_true")
+    p.add_argument("--verbose", action="store_true")
+    a = p.parse_args()
+    return asyncio.run(_run(a.apply, a.limit, a.sample, not a.no_throttle, a.verbose))
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())