Improve machines page: online status, formatted time, delete unbound placeholders.

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

app/routes.py

@@ -321,22 +321,12 @@ def register_routes(app: Flask) -> None:
     @app.get("/machines")
     @login_required
     def machines_page():
-        # 机器列表：管理员全看；普通用户只看与自己账户激活相关的机器
         u = current_user()
         with database.get_db() as conn:
-            if u["role"] == "admin":
-                items = database.list_machines(conn)
-            else:
-                cur = conn.execute(
-                    """
-                    SELECT DISTINCT m.* FROM machines m
-                    JOIN activations act ON act.machine_id = m.id
-                    WHERE act.account_id=?
-                    ORDER BY m.id DESC
-                    """,
-                    (u.get("account_id"),),
-                )
-                items = [database.row_to_dict(r) for r in cur.fetchall()]
+            items = database.list_machines_for_user(conn, u)
+        for m in items:
+            m["last_seen_fmt"] = _fmt_ts(m.get("last_seen_at"))
+            m["bound"] = bool(m.get("device_fingerprint"))
         return render_template("machines.html", items=items, is_admin=(u["role"] == "admin"))
 
     @app.post("/machines")
@@ -349,7 +339,7 @@ def register_routes(app: Flask) -> None:
                    VALUES(?,?,?,?,?)""",
                 (name, "", (request.form.get("note") or "").strip(), 1, database.now()),
             )
-        flash("机器已添加", "ok")
+        flash("机器已添加（预登记，激活后绑定指纹）", "ok")
         return redirect(url_for("machines_page"))
 
     @app.post("/machines/<int:mid>/note")
@@ -365,6 +355,17 @@ def register_routes(app: Flask) -> None:
         flash("机器标注已保存", "ok")
         return redirect(url_for("machines_page"))
 
+    @app.post("/machines/<int:mid>/delete")
+    @admin_required
+    def machines_delete(mid: int):
+        try:
+            with database.get_db() as conn:
+                database.delete_machine(conn, mid)
+            flash("机器已删除", "ok")
+        except ValueError as exc:
+            flash(str(exc), "error")
+        return redirect(url_for("machines_page"))
+
     # ---------- 下载 / 激活（管理员与用户都可发码；用户仅自己账户）----------
     @app.get("/download")
     @login_required