fix(bootstrap): backend lifespan 에서 DB migrate + symbols 시드 자동화

- main.py 의 lifespan 시작 시 idempotent migration 적용 + symbols 비어있으면 pykrx 로 전 종목 시드
- BOOTSTRAP_DISABLED=1 / SCHEDULER_DISABLED=1 env 로 비활성 가능 (테스트 용)
- 실패해도 서버는 뜨고 /health/db 가 진단 제공

리뷰어 지적 1번 (cold-start 시 /api/refresh 404) 해결.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/app/main.py

@@ -1,10 +1,12 @@
 from __future__ import annotations
 
 import logging
+import os
 from contextlib import asynccontextmanager
 
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
+from sqlalchemy import text
 
 from app.api.chart import router as chart_router
 from app.api.metrics import router as metrics_router
@@ -13,7 +15,7 @@ from app.api.predict import router as predict_router
 from app.api.refresh import router as refresh_router
 from app.api.symbols import router as symbols_router
 from app.config import settings
-from app.db.connection import ping as db_ping
+from app.db.connection import get_engine, ping as db_ping
 from app.fetch import dart as dart_mod
 from app.fetch import kis as kis_mod
 from app.pipelines.scheduler import shutdown_scheduler, start_scheduler
@@ -25,9 +27,51 @@ logging.basicConfig(
 logger = logging.getLogger(__name__)
 
 
+def _bootstrap_db() -> None:
+    """첫 부팅 자동화:
+      1) migrations/*.sql idempotent 적용 (timescale/pgvector 확장 + 스키마)
+      2) symbols 테이블 비어있으면 pykrx 로 전 종목 시드 (SEED 10 마크 포함)
+
+    BOOTSTRAP_DISABLED=1 이면 스킵 (테스트/CI 용). 어떤 단계든 실패해도 서버는
+    뜬다 — /health/db 가 진단을 알려준다.
+    """
+    if os.environ.get("BOOTSTRAP_DISABLED") == "1":
+        logger.info("bootstrap skipped (BOOTSTRAP_DISABLED=1)")
+        return
+
+    # 1) migrations
+    try:
+        from app.db.migrate import apply_all
+        res = apply_all()
+        logger.info("bootstrap migrate: %s", res)
+    except Exception:  # noqa: BLE001
+        logger.exception("bootstrap migrate failed")
+        return  # 스키마 없으면 시드 불가
+
+    # 2) symbols 시드 (비어있을 때만 — pykrx 호출이 비싸므로 항상 돌리지 않음)
+    try:
+        eng = get_engine()
+        with eng.connect() as conn:
+            row = conn.execute(text("SELECT COUNT(*) FROM symbols")).first()
+            count = int(row[0]) if row else 0
+        if count == 0:
+            logger.info("symbols empty — running initial seed")
+            from app.fetch.symbols_seed import seed_symbols
+            report = seed_symbols()
+            logger.info("bootstrap seed_symbols: %s", report)
+        else:
+            logger.info("symbols already populated (count=%d) — skip seed", count)
+    except Exception:  # noqa: BLE001
+        logger.exception("bootstrap seed_symbols failed")
+
+
 @asynccontextmanager
 async def lifespan(_: FastAPI):
+    _bootstrap_db()
     # 스케줄러는 옵션. CI/테스트에서 disable 하고 싶으면 SCHEDULER_DISABLED 같은 env 추가 가능.
+    if os.environ.get("SCHEDULER_DISABLED") == "1":
+        logger.info("scheduler skipped (SCHEDULER_DISABLED=1)")
+    else:
         try:
             start_scheduler()
         except Exception:  # noqa: BLE001