feat: postgres history-first 계약과 적재 경로 추가

- PostgreSQL history contract와 schema/validator를 추가했습니다.
- .NET history store, snapshot reader, repository, migration을 연결했습니다.
- history-first 운영 모델 문서와 daily signal tracking 문구를 정리했습니다.

tools/build_postgresql_history_snapshot_v1.py

@@ -0,0 +1,45 @@
+from __future__ import annotations
+
+import argparse
+import json
+from pathlib import Path
+
+from src.quant_engine.postgresql_history_store_v1 import DOMAIN_TABLES
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--dsn", required=True)
+    ap.add_argument("--out", default=str(ROOT / "Temp" / "postgresql_history_snapshot_v1.json"))
+    ap.add_argument("--limit", type=int, default=200)
+    args = ap.parse_args()
+
+    try:
+        from src.quant_engine.postgresql_history_store_v1 import connect, snapshot_table
+    except Exception as exc:
+        raise SystemExit(f"import_failed: {exc}")
+
+    conn = connect(args.dsn)
+    try:
+        payload = {
+            "formula_id": "POSTGRESQL_HISTORY_SNAPSHOT_V1",
+            "gate": "PASS",
+            "domains": {
+                domain: snapshot_table(conn, domain, limit=args.limit)
+                for domain in DOMAIN_TABLES
+            },
+        }
+    finally:
+        conn.close()
+
+    out = Path(args.out)
+    out.parent.mkdir(parents=True, exist_ok=True)
+    out.write_text(json.dumps(payload, ensure_ascii=False, indent=2, default=str), encoding="utf-8")
+    print(f"POSTGRESQL_HISTORY_SNAPSHOT_V1 gate=PASS out={out}")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())