fix(plugin): sanitize prompt fallback in before_prompt_build to prevent query pollution

The prompt fallback path bypassed sanitizeUserTextForCapture, allowing
Sender metadata blocks and timestamps to be sent as search queries to
the OpenViking API, causing irrelevant memories to rank highly.

Made-with: Cursor

Author: LinQiang391

examples/openclaw-plugin/index.ts

@@ -11,6 +11,7 @@ import {
   compileSessionPatterns,
   isTranscriptLikeIngest,
   extractLatestUserText,
+  sanitizeUserTextForCapture,
   shouldBypassSession,
 } from "./text-utils.js";
 import {
@@ -884,7 +885,7 @@ const contextEnginePlugin = {
       const eventObj = (event ?? {}) as { messages?: unknown[]; prompt?: string };
       const queryText =
         extractLatestUserText(eventObj.messages) ||
-        (typeof eventObj.prompt === "string" ? eventObj.prompt.trim() : "");
+        (typeof eventObj.prompt === "string" ? sanitizeUserTextForCapture(eventObj.prompt) : "");
       if (!queryText) {
         return;
       }