M4b：ai_provider 删除手术①-⑥——神识全面接管模型出口

- ① 后端删除 app/ai_provider/（38 文件，含 anthropic/openai 格式、billing、audio、embedding）、services/ai_provider_admin.py、core/config/model_config.py、tests/ai_provider/（21 文件）
- ② 连带退役 application/agent/（旧 Agent 循环/steer/follow-up/确认注册表）、application/skill_executor.py、app/skills/（python skills 孤儿）、endpoints/audio.py、application/imports.py（ProviderManager 消费方）；settings 端点收敛为生成偏好
- ③ runs.py 修剪：AgentRunRegistry/steer/follow-up/confirmations 端点退役，保留 list/get/events/cancel/stream；safety 确认改为直接落库裁决（pending→approved/denied）
- ④ 前端删除：models 页、ModelGatewayView、gateway.ts、GatewayPanel（玄关）、ModelGatewayPanel/ModelStrategyForm、audio.ts/useVoiceInput、网关类型与 mock；设置页收敛为外观/语言/通知
- ⑤ 配置收敛：config/models|providers|pricing.example.yaml 归档 shenshi/config/；.env.example 删 provider keys/MODEL_ENDPOINT_POOL/MODEL_CONFIG_PATH，收敛 SHENSHI_*
- ⑥ 验收：rg 审计灵台 Provider SDK import 与 ai_provider 引用归零；后端 528 passed（2 个预存失败经 HEAD 复跑验证与本手术无关）、前端 type-check+201 passed、神识 go vet+test、BFF 4 passed

backend/app/services/runtime.py

@@ -10,7 +10,6 @@ from app.core.security import redact_value
 from app.core.time import utc_now
 from app.db.session import AsyncSessionLocal
 from app.models.runtime import Event, Run
-from app.modules.runtime.events import EventStore
 from app.repositories import runtime as runtime_repo
 from app.repositories.json_utils import dumps
 from app.schemas.common import Page
@@ -21,7 +20,6 @@ from app.services.serializers import event_to_response, run_to_response
 
 TERMINAL_RUN_STATUS = {"completed", "failed", "cancelled", "interrupted"}
 TERMINAL_EVENT_TYPES = {"run.completed", "run.failed", "run.cancelled", "run.interrupted"}
-REQUIRES_CONFIRMATION_EVENT_TYPE = "tool.requires_confirmation"
 
 
 async def create_run(
@@ -215,20 +213,3 @@ async def list_run_event_responses(
             session, run_id, limit=limit, offset=offset
         )
         return [event_to_response(event) for event in events]
-
-
-async def confirmation_exists_in_run(
-    event_store: EventStore, run_id: str, confirmation_id: str
-) -> bool:
-    """失效感知：run 下是否曾经发过 ``tool.requires_confirmation`` 且 payload 含该 confirmation_id。
-
-    实现走 EventStore.list_by_run + Python 侧过滤，避免 PostgreSQL 专用 JSON 操作符，
-    兼容本地 SQLite。用于 approve/deny 端点在 Future 已失效时区分 410 与 404。
-    """
-    events = await event_store.list_by_run(run_id)
-    for event in events:
-        if event.type != REQUIRES_CONFIRMATION_EVENT_TYPE:
-            continue
-        if event.payload.get("confirmation_id") == confirmation_id:
-            return True
-    return False