fix: add 60s timeout to MiniMax VLM fetch call

The VLM image analysis fetch had no timeout, causing sessions to hang
indefinitely when the MiniMax API is slow or unresponsive. Other
vision/model API calls in the codebase already use timeouts. Adds
AbortSignal.timeout(60_000) consistent with image upload workloads.

Fixes #54139

src/agents/minimax-vlm.ts

@@ -85,6 +85,7 @@ export async function minimaxUnderstandImage(params: {
       "Content-Type": "application/json",
       "MM-API-Source": "OpenClaw",
     },
+    signal: AbortSignal.timeout(60_000),
     body: JSON.stringify({
       prompt,
       image_url: imageDataUrl,