Add SSE second-level dashboard stream and 2s client heartbeat.

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

app/routes.py

@@ -3,11 +3,13 @@ from __future__ import annotations
 
 import json
 import secrets
+import time
 from datetime import datetime
 from functools import wraps
 
 from flask import (
     Flask,
+    Response,
     flash,
     g,
     jsonify,
@@ -16,6 +18,7 @@ from flask import (
     request,
     send_from_directory,
     session,
+    stream_with_context,
     url_for,
 )
 
@@ -222,42 +225,69 @@ def register_routes(app: Flask) -> None:
         data = _dashboard_payload(current_user())
         return render_template("dashboard.html", **data)
 
+    def _dashboard_live_dict(u: dict) -> dict:
+        data = _dashboard_payload(u)
+        return {
+            "ok": True,
+            "ts": database.now(),
+            "online_count": data["online_count"],
+            "machine_count": data["machine_count"],
+            "online_machines": [
+                {
+                    "id": m["id"],
+                    "name": m.get("name") or f"#{m['id']}",
+                    "last_seen_at": m.get("last_seen_at"),
+                    "last_seen_fmt": _fmt_ts(m.get("last_seen_at")),
+                    "online": True,
+                }
+                for m in data["online_machines"]
+            ],
+            "trades": [
+                {
+                    "id": t["id"],
+                    "time_fmt": t.get("time_fmt"),
+                    "symbol": t.get("symbol"),
+                    "side": t.get("side"),
+                    "volume": t.get("volume"),
+                    "profit": t.get("profit"),
+                    "account_name": t.get("account_name"),
+                    "machine_name": t.get("machine_name"),
+                    "ticket": t.get("ticket"),
+                }
+                for t in data["trades"]
+            ],
+        }
+
     @app.get("/api/dashboard/live")
     @login_required
     def dashboard_live():
-        """总览轮询：在线机器 + 实时成交。"""
-        data = _dashboard_payload(current_user())
-        return jsonify(
-            {
-                "ok": True,
-                "online_count": data["online_count"],
-                "machine_count": data["machine_count"],
-                "online_machines": [
-                    {
-                        "id": m["id"],
-                        "name": m.get("name") or f"#{m['id']}",
-                        "last_seen_at": m.get("last_seen_at"),
-                        "last_seen_fmt": _fmt_ts(m.get("last_seen_at")),
-                        "online": True,
-                    }
-                    for m in data["online_machines"]
-                ],
-                "trades": [
-                    {
-                        "id": t["id"],
-                        "time_fmt": t.get("time_fmt"),
-                        "symbol": t.get("symbol"),
-                        "side": t.get("side"),
-                        "volume": t.get("volume"),
-                        "profit": t.get("profit"),
-                        "account_name": t.get("account_name"),
-                        "machine_name": t.get("machine_name"),
-                        "ticket": t.get("ticket"),
-                    }
-                    for t in data["trades"]
-                ],
-            }
-        )
+        """总览快照（兼容轮询）。"""
+        return jsonify(_dashboard_live_dict(current_user()))
+
+    @app.get("/api/dashboard/stream")
+    @login_required
+    def dashboard_stream():
+        """秒级 SSE 推送：在线机器 + 实时成交。"""
+        u = current_user()
+
+        @stream_with_context
+        def event_stream():
+            # 立即推一帧，后续约每秒一帧
+            while True:
+                try:
+                    payload = json.dumps(_dashboard_live_dict(u), ensure_ascii=False)
+                    yield f"data: {payload}\n\n"
+                except GeneratorExit:
+                    return
+                except Exception:
+                    yield 'event: error\ndata: {"ok":false}\n\n'
+                time.sleep(1)
+
+        resp = Response(event_stream(), mimetype="text/event-stream")
+        resp.headers["Cache-Control"] = "no-cache"
+        resp.headers["X-Accel-Buffering"] = "no"
+        resp.headers["Connection"] = "keep-alive"
+        return resp
 
     # ---------- 账户（仅管理员创建）----------
     @app.get("/accounts")
@@ -404,7 +434,7 @@ def register_routes(app: Flask) -> None:
                 ).fetchall()
             activations = []
             now_ts = database.now()
-            online_sec = 180  # 3 分钟内有心跳视为在线
+            online_sec = database.ONLINE_SECONDS
             for r in acts:
                 item = database.row_to_dict(r)
                 last = item.get("machine_last_seen")