refactor: 平台改为代码内置 provider 架构，一次性迁移现有数据 - 新增 app/providers：BalanceProvider 基类 + DeepSeek 适配器 + 注册表 - platforms 表去除 method/url/headers/body/balance_path，新增 provider_id - 现有数据库已一次性迁移（备份 data/monitor.db.bak-v1），不保留迁移工具 - 平台 UI 改为选择内置提供方；fetcher/monitor 走 provider 构建请求与解析 - 表达式引擎（运算符/函数）随架构保留，供 provider 内部使用 - 测试更新至 provider 模式，共 92 个

app/providers/deepseek.py

@@ -0,0 +1,28 @@
+"""DeepSeek 开放平台余额。
+
+接口：GET https://api.deepseek.com/user/balance
+响应：{"is_available": true, "balance_infos": [{"currency": "CNY", "total_balance": "1.34", ...}]}
+"""
+
+from __future__ import annotations
+
+from app.expr import evaluate_balance
+from app.providers.base import BalanceProvider
+
+
+class DeepSeekProvider(BalanceProvider):
+    id = "deepseek"
+    name = "DeepSeek"
+    currency = "CNY"
+    icon = "DeepSeek"
+    description = "DeepSeek 开放平台余额（GET /user/balance，Bearer 认证）"
+
+    def build_request(self, api_key: str) -> tuple[str, dict, str | None]:
+        return (
+            "https://api.deepseek.com/user/balance",
+            {"Accept": "application/json", "Authorization": f"Bearer {api_key}"},
+            None,
+        )
+
+    def extract_balance(self, data: object) -> float:
+        return evaluate_balance(data, "balance_infos[0].total_balance")