feat: 多平台 Coding Plan 统一管理系统初始实现

- 支持 MiniMax/OpenAI/Google Gemini/智谱/Kimi 五个平台
- 插件化 Provider 架构，自动发现注册
- 多维度 QuotaRule 额度追踪（固定间隔/自然周期/API同步/手动）
- OpenAI + Anthropic 兼容 API 代理，SSE 流式转发
- Model 路由表 + 额度耗尽自动 fallback
- 多媒体任务队列（图片/语音/视频）
- Vue3 + Tailwind 单文件 Web 仪表盘
- Docker 一键部署

Made-with: Cursor

app/providers/__init__.py

@@ -0,0 +1,50 @@
+"""Provider 自动发现 + 注册表"""
+
+from __future__ import annotations
+
+import importlib
+import pkgutil
+from pathlib import Path
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from app.providers.base import BaseProvider, Capability
+
+
+class ProviderRegistry:
+    """全局 Provider 注册表，启动时自动扫描 providers/ 目录"""
+
+    _providers: dict[str, "BaseProvider"] = {}
+
+    @classmethod
+    def auto_discover(cls):
+        """扫描当前包下所有模块，注册 BaseProvider 子类实例"""
+        from app.providers.base import BaseProvider as _Base
+
+        package_dir = Path(__file__).parent
+        for info in pkgutil.iter_modules([str(package_dir)]):
+            if info.name in ("base", "__init__"):
+                continue
+            mod = importlib.import_module(f"app.providers.{info.name}")
+            for attr_name in dir(mod):
+                attr = getattr(mod, attr_name)
+                if (
+                    isinstance(attr, type)
+                    and issubclass(attr, _Base)
+                    and attr is not _Base
+                    and getattr(attr, "name", "")
+                ):
+                    instance = attr()
+                    cls._providers[instance.name] = instance
+
+    @classmethod
+    def get(cls, name: str) -> "BaseProvider | None":
+        return cls._providers.get(name)
+
+    @classmethod
+    def all(cls) -> dict[str, "BaseProvider"]:
+        return dict(cls._providers)
+
+    @classmethod
+    def by_capability(cls, cap: "Capability") -> list["BaseProvider"]:
+        return [p for p in cls._providers.values() if cap in p.capabilities]