feat(proxy): 节点状态简化、连接事件记录、可靠性指标与批量删除

- 移除 UNHEALTHY 中间状态，节点状态简化为 ONLINE/OFFLINE
- 新增 proxy_node_events 表记录 tunnel 连接/断开/错误事件
- 新增 failed_requests/dns_failures/stream_errors 可靠性指标（增量累加）
- tunnel 重连改为固定 1s 延迟，移除指数退避逻辑
- resolver/service 改为以 TunnelManager 内存状态判断节点可用性，避免 DB 竞态
- 修正 Claude cache_control 字段格式，使用 ttl 字段控制缓存时长
- 移除前端手动勾选 capability 的 UI，改为从价格配置自动推断
- 新增全局模型批量删除 API，替换前端并行单个删除

alembic/versions/20260228_1238_48afe197cc15_proxy_node_metrics_and_events.py

@@ -0,0 +1,114 @@
+"""proxy_node_metrics_and_events
+
+Revision ID: 48afe197cc15
+Revises: b2c3d4e5f6a7
+Create Date: 2026-02-28 04:33:11.201185+00:00
+
+"""
+
+import sqlalchemy as sa
+from sqlalchemy import inspect
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "48afe197cc15"
+down_revision = "b2c3d4e5f6a7"
+branch_labels = None
+depends_on = None
+
+
+def _column_exists(table_name: str, column_name: str) -> bool:
+    bind = op.get_bind()
+    insp = inspect(bind)
+    columns = [c["name"] for c in insp.get_columns(table_name)]
+    return column_name in columns
+
+
+def _table_exists(table_name: str) -> bool:
+    bind = op.get_bind()
+    insp = inspect(bind)
+    return table_name in insp.get_table_names()
+
+
+def upgrade() -> None:
+    # proxy_nodes: 新增错误指标字段
+    if not _column_exists("proxy_nodes", "failed_requests"):
+        op.add_column(
+            "proxy_nodes",
+            sa.Column(
+                "failed_requests",
+                sa.BigInteger(),
+                nullable=False,
+                server_default="0",
+                comment="累计失败请求数",
+            ),
+        )
+    if not _column_exists("proxy_nodes", "dns_failures"):
+        op.add_column(
+            "proxy_nodes",
+            sa.Column(
+                "dns_failures",
+                sa.BigInteger(),
+                nullable=False,
+                server_default="0",
+                comment="累计 DNS 失败数",
+            ),
+        )
+    if not _column_exists("proxy_nodes", "stream_errors"):
+        op.add_column(
+            "proxy_nodes",
+            sa.Column(
+                "stream_errors",
+                sa.BigInteger(),
+                nullable=False,
+                server_default="0",
+                comment="累计流错误数",
+            ),
+        )
+
+    # proxy_node_events: 连接事件表
+    if not _table_exists("proxy_node_events"):
+        op.create_table(
+            "proxy_node_events",
+            sa.Column("id", sa.BigInteger(), autoincrement=True, nullable=False),
+            sa.Column("node_id", sa.String(length=36), nullable=False),
+            sa.Column(
+                "event_type",
+                sa.String(length=20),
+                nullable=False,
+                comment="事件类型: connected, disconnected, error",
+            ),
+            sa.Column(
+                "detail",
+                sa.String(length=500),
+                nullable=True,
+                comment="事件详情（如断开原因）",
+            ),
+            sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+            sa.ForeignKeyConstraint(["node_id"], ["proxy_nodes.id"], ondelete="CASCADE"),
+            sa.PrimaryKeyConstraint("id"),
+        )
+        op.create_index(
+            "idx_proxy_node_events_node_created",
+            "proxy_node_events",
+            ["node_id", "created_at"],
+        )
+        op.create_index(
+            op.f("ix_proxy_node_events_node_id"),
+            "proxy_node_events",
+            ["node_id"],
+        )
+
+
+def downgrade() -> None:
+    if _table_exists("proxy_node_events"):
+        op.drop_index(op.f("ix_proxy_node_events_node_id"), table_name="proxy_node_events")
+        op.drop_index("idx_proxy_node_events_node_created", table_name="proxy_node_events")
+        op.drop_table("proxy_node_events")
+    if _column_exists("proxy_nodes", "stream_errors"):
+        op.drop_column("proxy_nodes", "stream_errors")
+    if _column_exists("proxy_nodes", "dns_failures"):
+        op.drop_column("proxy_nodes", "dns_failures")
+    if _column_exists("proxy_nodes", "failed_requests"):
+        op.drop_column("proxy_nodes", "failed_requests")