feat: 新增 Kiro 适配器、OAuth 改进与多项功能增强

- 新增 Kiro provider 适配器（EventStream 协议解析、令牌管理、用量追踪）
- 重构 OAuth 账户管理与统一配额机制
- 重构 Handler 基类（CLI adapter/handler、请求构建器、流处理器）
- 增强缓存监控后端 API 与前端可视化
- 改进 Gemini 格式标准化器与请求头处理
- Antigravity/Codex 适配器更新，移除旧 metadata_collector
- 新增数据库迁移：proxy provider API keys
- 前端 UI 多项优化

Co-Authored-By: AAEE86 <ppk0227@hotmail.com>

alembic/versions/20260208_1500_6d7e8f9a0b1c_add_proxy_to_provider_api_keys.py

@@ -0,0 +1,47 @@
+"""Add proxy column to provider_api_keys for per-key proxy configuration
+
+Revision ID: 6d7e8f9a0b1c
+Revises: 5c6d7e8f9a0b
+Create Date: 2026-02-08 15:00:00.000000
+
+"""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from sqlalchemy import inspect
+
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = "6d7e8f9a0b1c"
+down_revision: str | None = "5c6d7e8f9a0b"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def column_exists(table_name: str, column_name: str) -> bool:
+    bind = op.get_bind()
+    inspector = inspect(bind)
+    columns = [c["name"] for c in inspector.get_columns(table_name)]
+    return column_name in columns
+
+
+def upgrade() -> None:
+    if not column_exists("provider_api_keys", "proxy"):
+        op.add_column(
+            "provider_api_keys",
+            sa.Column(
+                "proxy",
+                sa.JSON(),
+                nullable=True,
+                comment="Key 级别代理配置（覆盖 Provider 级别代理），如 {node_id, enabled}",
+            ),
+        )
+
+
+def downgrade() -> None:
+    if column_exists("provider_api_keys", "proxy"):
+        op.drop_column("provider_api_keys", "proxy")