feat(config): 运行时配置体系①——LLM 多厂商独立组落 models.json + 面板落盘 + 热更新

- runtimeconfig/models.go: models.json 承载 [{id,provider,baseUrl,apiKey,model,fallback?,multimodal?}] 多厂商独立组(首项=生效)
- LoadModels 优先文件/回退env(GroupFromEnv), SaveModels(0600+tmp原子写), Activate/Upsert/MaskedKey脱敏
- 面板 POST /admin/llm 落盘 models.json(取代temporary内存) + GET 列组(脱敏)
- runtime/model/runtime.go: RuntimeLLM(adapter+router) atomic快照可热替换, Reload 重建不中断进行中请求; per-role路由用接口
- wire 用 NewRuntimeLLM(adapter+router), 保留 a.modelAdapter(=runtime stack, 审查模型随热更新)
- .env 退兜底(.env.example注明); apiKey不打印/Config()脱敏/热更新不中断
- 全仓 go build/vet/test 绿(54包)+交叉编译+前端build绿(79模块); api-client v0.15已同步
- 遗留: vision ModelInfo 仍读静态env(后续纳入); 保存组=生效组(第一版语义)

frontend/web/src/lib/api.ts

@@ -18,6 +18,7 @@ import type {
   ChannelTestResult,
   ChatMessage,
   ChatSyncResult,
+  LlmProviderRequest,
   LlmTestRequest,
   LlmTestResult,
   LoginResult,
@@ -452,16 +453,14 @@ export function adminRunAutomation(id: string): Promise<AutomationRunResult> {
 export function adminDeleteAutomation(id: string): Promise<{ id: string; deleted: boolean }> {
   return request<{ id: string; deleted: boolean }>(`/admin/automations/${encodeURIComponent(id)}`, { method: "DELETE" });
 }
-/** POST /api/v1/admin/llm — records a provider for the process lifetime (temporary). */
-export function adminAddLlmProvider(req: {
-  id?: string;
-  name: string;
-  baseUrl?: string;
-  model: string;
-  multimodal?: boolean;
-  fallback?: string;
-}): Promise<{ provider: AdminLlmProvider; temporary: boolean }> {
-  return request<{ provider: AdminLlmProvider; temporary: boolean }>("/admin/llm", {
+/** POST /api/v1/admin/llm — saves a provider group to models.json and hot-reloads
+ *  the running LLM stack (design/04 §3.1). The provider is the wire protocol. */
+export function adminAddLlmProvider(req: LlmProviderRequest): Promise<{
+  provider: AdminLlmProvider;
+  persisted: boolean;
+  path?: string;
+}> {
+  return request<{ provider: AdminLlmProvider; persisted: boolean; path?: string }>("/admin/llm", {
     method: "POST",
     body: JSON.stringify(req),
   });