Fix MCP tool timeout: pass mcp_timeout as AI SDK streamText stepMs

The AI SDK streamText() defaults stepMs to 120s, which covers the entire
step including tool execution. This caused MCP tool calls to timeout at
120s even when experimental.mcp_timeout was configured to a much larger
value, because the AI SDK step timeout fired before the MCP-level timeout.

Co-Authored-By: Claude Opus 4.7 <[email protected]>

Author: KonghaYao

packages/opencode/src/session/llm.ts

@@ -334,6 +334,9 @@ const live: Layer.Layer<
         : undefined
 
       return streamText({
+        timeout: cfg.experimental?.mcp_timeout
+          ? { stepMs: cfg.experimental.mcp_timeout }
+          : undefined,
         onError(error) {
           l.error("stream error", {
             error,