Add SIM/LIVE switch with API keys saved to .env and OKX live executor.

Enable settings UI for mode/keys, gate strategy start when LIVE is not ready, and stop PM2 from forcing MODE=SIM.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/models/db.py

@@ -40,7 +40,8 @@ CREATE TABLE IF NOT EXISTS groups (
   realized_pnl REAL DEFAULT 0,
   fees REAL DEFAULT 0,
   slip_cost REAL DEFAULT 0,
-  note TEXT
+  note TEXT,
+  exec_mode TEXT
 );
 
 CREATE TABLE IF NOT EXISTS fills (
@@ -58,6 +59,7 @@ CREATE TABLE IF NOT EXISTS fills (
   slip REAL NOT NULL,
   notional REAL NOT NULL,
   ts_ms INTEGER NOT NULL,
+  exec_mode TEXT,
   FOREIGN KEY(group_id) REFERENCES groups(group_id)
 );
 
@@ -140,8 +142,26 @@ class Database:
         self._conn.execute("PRAGMA journal_mode=WAL;")
         self._conn.executescript(_SCHEMA)
         self._conn.commit()
+        self._migrate_columns()
         self._ensure_seed()
 
+    def _migrate_columns(self) -> None:
+        """幂等补列：exec_mode。"""
+        with self._lock:
+            for table, col, decl in (
+                ("groups", "exec_mode", "TEXT"),
+                ("fills", "exec_mode", "TEXT"),
+            ):
+                cols = {
+                    str(r[1])
+                    for r in self._conn.execute(f"PRAGMA table_info({table})").fetchall()
+                }
+                if col not in cols:
+                    self._conn.execute(
+                        f"ALTER TABLE {table} ADD COLUMN {col} {decl}"
+                    )
+            self._conn.commit()
+
     def close(self) -> None:
         with self._lock:
             self._conn.close()