feat(frontend): make SSE idle timeout configurable via VIBE_TRADING_SSE_TIMEOUT (#157)

The frontend safety timeout was hardcoded at 90 s, causing false
"Execution timed out" toasts for users running slow local models
(e.g. Ollama on limited VRAM or CPU).

- Backend: expose `sse_timeout_seconds` in `LLMSettingsResponse`,
  reading from `VIBE_TRADING_SSE_TIMEOUT` env var (default 90 s)
- Frontend: fetch the value from `/settings/llm` on mount and use it
  instead of the hardcoded 90 000 ms constant
- `.env.example`: document the new variable in the Agent Tuning section

Co-authored-by: Sky <985369746@qq.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

agent/.env.example

@@ -139,3 +139,6 @@ TUSHARE_TOKEN=your-tushare-token
 # SUBAGENT_TIMEOUT=300
 # SUBAGENT_MAX_ITER=25
 # TOKEN_THRESHOLD=40000
+# Frontend SSE idle timeout in seconds before showing "Execution timed out".
+# Increase when using slow local models (e.g. Ollama on CPU/limited VRAM).
+# VIBE_TRADING_SSE_TIMEOUT=90

agent/api_server.py

@@ -170,6 +170,7 @@ class LLMSettingsResponse(BaseModel):
     timeout_seconds: int
     max_retries: int
     reasoning_effort: str
+    sse_timeout_seconds: int
     env_path: str
     providers: List[LLMProviderOption]
 
@@ -926,6 +927,7 @@ def _build_llm_settings_response(values: Optional[Dict[str, str]] = None) -> LLM
         timeout_seconds=_coerce_int(env_values.get("TIMEOUT_SECONDS", "120"), 120),
         max_retries=_coerce_int(env_values.get("MAX_RETRIES", "2"), 2),
         reasoning_effort=env_values.get("LANGCHAIN_REASONING_EFFORT", "").strip().lower(),
+        sse_timeout_seconds=_coerce_int(env_values.get("VIBE_TRADING_SSE_TIMEOUT", "90"), 90),
         env_path=_project_relative_path(ENV_PATH),
         providers=LLM_PROVIDERS,
     )

frontend/src/lib/api.ts

@@ -232,6 +232,7 @@ export interface LLMSettings {
   timeout_seconds: number;
   max_retries: number;
   reasoning_effort: string;
+  sse_timeout_seconds: number;
   env_path: string;
   providers: LLMProviderOption[];
 }

frontend/src/pages/Agent.tsx

@@ -212,6 +212,7 @@ export function Agent() {
   const pendingGoalSessionRef = useRef<string | null>(null);
   const [showScrollBtn, setShowScrollBtn] = useState(false);
   const lastEventRef = useRef(0);
+  const sseTimeoutMsRef = useRef(90_000);
 
   /* tool_progress coalescing — keep latest payload per-tool, flush once per rAF. */
   const pendingProgressRef = useRef<Map<string, NonNullable<ToolCallEntry["progress"]>>>(new Map());
@@ -709,11 +710,17 @@ export function Agent() {
 
   useEffect(() => () => doDisconnect(), [doDisconnect]);
 
-  /* Safety timeout: if streaming but no SSE event for 90s, reset to idle */
+  useEffect(() => {
+    api.getLLMSettings().then((s) => {
+      sseTimeoutMsRef.current = s.sse_timeout_seconds * 1000;
+    }).catch(() => {});
+  }, []);
+
+  /* Safety timeout: if streaming but no SSE event for sseTimeoutMsRef.current ms, reset to idle */
   useEffect(() => {
     if (status !== "streaming") return;
     const timer = setInterval(() => {
-      if (lastEventRef.current && Date.now() - lastEventRef.current > 90_000 && act().status === "streaming") {
+      if (lastEventRef.current && Date.now() - lastEventRef.current > sseTimeoutMsRef.current && act().status === "streaming") {
         act().setStatus("idle");
         toast.warning("Execution timed out, automatically stopped");
       }