feat(principles): canonical_statement synthesis service + throttled backfill (Phase E groundwork, #152)

Grounded (INV-AH) multi-instance synthesis with drift guard + chair gate
(pending_review, G10). Single path used by backfill, MCP tool, nightly drain.
HELD from production run pending the principles-redesign (rename+cull, #152).

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

scripts/halacha_panel_approve.py

@@ -50,24 +50,17 @@ from pathlib import Path
 
 import httpx
 
-from legal_mcp.services import claude_session, db
+from legal_mcp.services import db, panel_judges
+# Judges are the shared primitive (G2) — #152 lifted them to services/panel_judges.
+from legal_mcp.services.panel_judges import (
+    DEEPSEEK_KEY,
+    GEMINI_KEY,
+    judge_claude,
+    judge_deepseek,
+    judge_gemini,
+)
 
-# ── keys (local files, same pattern as the other local judges) ──
-
-def _env_key(name: str, *files: str) -> str:
-    for f in files:
-        p = Path(f).expanduser()
-        if p.exists():
-            for line in p.read_text().splitlines():
-                if line.startswith(name + "="):
-                    return line.split("=", 1)[1].strip()
-    return os.environ.get(name, "")
-
-
-DEEPSEEK_KEY = _env_key("DEEPSEEK_API_KEY", "~/.hermes/profiles/deepseek/.env", "~/.env")
-# canonical Infisical name is GOOGLE_GEMINI_API_KEY (/external-apis/gemini); accept
-# the bare GEMINI_API_KEY too for back-compat.
-GEMINI_KEY = _env_key("GOOGLE_GEMINI_API_KEY", "~/.env") or _env_key("GEMINI_API_KEY", "~/.env")
+_bool = panel_judges.to_bool
 
 # ── the two coarse questions (the reliable axis — NOT the fuzzy sub-type) ──
 
@@ -99,62 +92,6 @@ def _nli_user(h: dict) -> str:
     return f"כלל:\n{h.get('rule_statement') or ''}\n\nציטוט:\n{h.get('supporting_quote') or ''}"
 
 
-# ── three judges, one signature: (system, user) -> dict|None ──
-
-async def judge_claude(system: str, user: str) -> dict | None:
-    try:
-        return await claude_session.query_json(user, system=system)
-    except Exception:
-        return None
-
-
-async def judge_deepseek(client: httpx.AsyncClient, system: str, user: str) -> dict | None:
-    if not DEEPSEEK_KEY:
-        return None
-    try:
-        r = await client.post(
-            "https://api.deepseek.com/v1/chat/completions",
-            headers={"Authorization": f"Bearer {DEEPSEEK_KEY}", "Content-Type": "application/json"},
-            json={"model": "deepseek-chat", "temperature": 0, "max_tokens": 120,
-                  "response_format": {"type": "json_object"},
-                  "messages": [{"role": "system", "content": system},
-                               {"role": "user", "content": user}]},
-            timeout=90,
-        )
-        r.raise_for_status()
-        return json.loads(r.json()["choices"][0]["message"]["content"])
-    except Exception:
-        return None
-
-
-async def judge_gemini(client: httpx.AsyncClient, system: str, user: str) -> dict | None:
-    if not GEMINI_KEY:
-        return None
-    try:
-        r = await client.post(
-            f"https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key={GEMINI_KEY}",
-            headers={"Content-Type": "application/json"},
-            json={"system_instruction": {"parts": [{"text": system}]},
-                  "contents": [{"parts": [{"text": user}]}],
-                  "generationConfig": {"temperature": 0, "maxOutputTokens": 4000,
-                                       "responseMimeType": "application/json"}},
-            timeout=90,
-        )
-        r.raise_for_status()
-        return json.loads(r.json()["candidates"][0]["content"]["parts"][0]["text"])
-    except Exception:
-        return None
-
-
-def _bool(d: dict | None, key: str) -> bool | None:
-    if not isinstance(d, dict) or key not in d:
-        return None
-    v = d[key]
-    if isinstance(v, bool):
-        return v
-    return str(v).strip().lower() in ("true", "1", "yes", "כן")
-
-
 async def panel_vote(client, system, user, key) -> dict:
     """Run all three judges; return per-judge bools + the verdict."""
     c, ds, gm = await asyncio.gather(