refactor: retire price_events.json completely — DB is the only store

User directive: no JSON, retire it fully, fix all related code.

Changes:
- price_monitor.py: record_event writes DB only; removed EVENTS_PATH/
  load_events/save_events entirely
- strategy_feedback.py: price events read from DB only (removed JSON fallback)
- system_health_check.py: removed price_events.json from file-check list,
  DB-only event stats (was showing 0/0 due to wrong-DB resolution)
- mo_config.py: removed dead price_events_path property (no callers)
- mofin_health.py: price_events freshness reads DB table (authoritative now)
- mofin_db.py: DATA_DIR/DB_PATH now ABSOLUTE (/home/hmo/MoFin/data) —
  was relative __file__.parent, so each hardlinked copy of mofin_db.py
  resolved to a DIFFERENT database (canonical vs web-dashboard vs
  profile-local third DB with 0 rows of everything except market_snapshots).
  This fragmentation was the real cause of health checks reading empty tables.
- Unified all 4 mofin_db copies (root/scripts/deploy/profile) via hardlink
- price_events.json archived to trashbox (fully backfilled: 6353 rows in DB)

Verified:
- record_event lands in DB only, JSON not recreated
- system_health_check: 历史事件 6353 / 今日事件 2965 (was 0/0)
- strategy_feedback + price_monitor full runs clean

scripts/price_monitor.py

@@ -12,7 +12,6 @@ from mo_data import read_decisions
 
 BREACH_PATH = "/home/hmo/.hermes/zone_breach.json"
 STATE_PATH = "/home/hmo/.hermes/price_trigger_state.json"
-EVENTS_PATH = "/home/hmo/web-dashboard/data/price_events.json"
 
 # DB 模块（同步实时价到 mofin.db）
 sys.path.insert(0, "/home/hmo/MoFin")
@@ -319,37 +318,28 @@ def save_breaches(data):
         json.dump(data, f, ensure_ascii=False, indent=2)
 
 
-def load_events():
-    try:
-        with open(EVENTS_PATH) as f:
-            return json.load(f)
-    except:
-        return {"events": []}
-
-
-def save_events(events):
-    os.makedirs(os.path.dirname(EVENTS_PATH), exist_ok=True)
-    with open(EVENTS_PATH, 'w') as f:
-        json.dump(events, f, ensure_ascii=False, indent=2)
-
-
 def record_event(code, name, event_type, price, trigger_value, event_label=""):
-    """记录一次价格触发事件到 price_events.json"""
-    events = load_events()
+    """记录一次价格触发事件到 DB price_events 表（唯一权威存储，JSON 已退役）。
+
+    price_events.code 有 FK -> stocks(code)，未注册的股票（新候选/港股）
+    先注册再写事件，否则 FK 失败事件丢失。
+    """
     now = datetime.now().isoformat()
-    events["events"].append({
-        "code": code,
-        "name": name,
-        "event_type": event_type,  # entry_zone, stop_loss, take_profit, exit_zone
-        "price": round(price, 2),
-        "trigger_value": trigger_value,
-        "event_label": event_label,
-        "timestamp": now,
-        "date": datetime.now().strftime("%Y-%m-%d"),
-    })
-    # 保留最近10000条
-    events["events"] = events["events"][-10000:]
-    save_events(events)
+
+    if HAS_DB:
+        try:
+            from mofin_db import get_conn, write_price_event
+            _c = get_conn()
+            _exch, _typ = ("HK", "H") if len(str(code)) == 5 else (("SH", "A") if str(code).startswith(("6", "9")) else ("SZ", "A"))
+            _c.execute("INSERT OR IGNORE INTO stocks (code, name, exchange, type, updated_at) VALUES (?,?,?,?,?)",
+                       (str(code), name or str(code), _exch, _typ, now))
+            _c.commit()
+            write_price_event(_c, code=code, name=name, event_type=event_type,
+                              price=round(price, 2), trigger_value=str(trigger_value),
+                              event_label=event_label)
+            _c.close()
+        except Exception as e:
+            print(f"[price_events DB写入失败] {e}", file=sys.stderr)
 
 
 def get_trigger_zones(trigger):
@@ -581,7 +571,7 @@ def run_once(round_label=""):
     # === 第三步：买入区偏离检测 + 自动重评 ===
     reassesed_codes = []
     # 先做急跌检测（仅持仓，自选股不推送暴跌告警）
-    holdings_codes = {d["code"] for d in active if d.get("shares", 0) > 0}
+    holdings_codes = {d["code"] for d in active if (d.get("shares") or 0) > 0}
     for d in active:
         code = d["code"]
         # 非持仓跳过