fix(tz): timezone-aware datetimes — unblock TZ=Asia/Jerusalem (#210)

Backend follow-up to INV-UI9 (X6 §"אודיט-נלווה"): make server-side
datetimes explicit so flipping the container to TZ=Asia/Jerusalem cannot
silently skew stored or displayed timestamps. Storage stays UTC; human
display is Israel time.

- audit.py: naive datetime.utcnow() → datetime.now(timezone.utc) for the
  TIMESTAMPTZ audit_log.created_at. Under TZ=Asia/Jerusalem the naive UTC
  wall-clock would be read as Israel-local and stored ~3h off. (§6: no
  silent skew.)
- calibrate_effort.py: _ts() report stamp now Israel-time via
  ZoneInfo("Asia/Jerusalem") with a filename-safe "-IL" suffix (script runs
  on the UTC host); added a labeled "שעון ישראל" line to the report header
  so the chair-facing timestamp is unambiguous. --self-test still ALL PASS.
- research_md.py: display fields made deterministic Israel-tz —
  update_chair_position timestamp (datetime.now(IL_TZ)) and parse() mtime
  (datetime.fromtimestamp(..., tz=IL_TZ)) — correct regardless of process TZ.

Left intentionally Israel-local-day date.today()/year-cutoff call sites
untouched (drafting/party_claims_summary/block_writer/court_fetch_supreme)
— a Jerusalem committee wants the Israel calendar day; they resolve
correctly once TZ flips.

Invariants: INV-UI9 (store-UTC / display-Israel, server side); §6
(timezone-aware datetimes, no silent ~3h skew).

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

scripts/calibrate_effort.py

@@ -58,8 +58,9 @@ import json
 import logging
 import os
 import sys
-from datetime import datetime, timezone
+from datetime import datetime
 from pathlib import Path
+from zoneinfo import ZoneInfo
 from statistics import mean
 
 logger = logging.getLogger(__name__)
@@ -344,8 +345,17 @@ async def _run(args, ts: str) -> dict:
     return {"dry_run": False, "grid": grid_summary, "by_block": by_block}
 
 
+IL_TZ = ZoneInfo("Asia/Jerusalem")
+
+
 def _ts() -> str:
-    return datetime.now(timezone.utc).strftime("%Y%m%dT%H%M%SZ")
+    """Filename-safe report stamp in Israel time (INV-UI9: human-facing display).
+
+    This script runs on the host, which is UTC, so a process-clock stamp would
+    mislead the chair. We pin Asia/Jerusalem and suffix ``IL`` (instead of a bare
+    ``Z``) so the displayed/filename time is unambiguously Israel-local.
+    """
+    return datetime.now(IL_TZ).strftime("%Y%m%dT%H%M%S-IL")
 
 
 def _write_report(result: dict, ts: str) -> tuple[Path, Path]:
@@ -356,8 +366,10 @@ def _write_report(result: dict, ts: str) -> tuple[Path, Path]:
 
     g = result["grid"]
     n = g["n_finals"]
+    il_now = datetime.now(IL_TZ).strftime("%Y-%m-%d %H:%M")
     lines = [
         f"# #208 — כיול model×effort מול הסופיים — {ts}\n",
+        f"> נוצר: {il_now} (שעון ישראל · Asia/Jerusalem)\n",
         f"> ⚠️ **גודל-מדגם: {n} סופיים** ({', '.join(g['finals']) or '—'}). "
         "זוהי **עדות-כיוון, לא רגרסיה** — מעט תיקים בעלי סופי-עלוי. "
         "ההמלצה אדוויזורית; ההכרעה בידי היו\"ר/המפעיל.\n",