fix(slack): detect control commands when message starts with @mention (#14142)

Merged via /review-pr-v2 -> /prepare-pr-v2 -> /merge-pr-v2.

Prepared head SHA: cb0b4f6a3b
Co-authored-by: beefiker <55247450+beefiker@users.noreply.github.com>
Co-authored-by: gumadeiras <gumadeiras@gmail.com>
Reviewed-by: @gumadeiras

src/slack/monitor/commands.ts

@@ -1,5 +1,16 @@
 import type { SlackSlashCommandConfig } from "../../config/config.js";
 
+/**
+ * Strip Slack mentions (<@U123>, <@U123|name>) so command detection works on
+ * normalized text. Use in both prepare and debounce gate for consistency.
+ */
+export function stripSlackMentionsForCommandDetection(text: string): string {
+  return (text ?? "")
+    .replace(/<@[^>]+>/g, " ")
+    .replace(/\s+/g, " ")
+    .trim();
+}
+
 export function normalizeSlackSlashCommandName(raw: string) {
   return raw.replace(/^\/+/, "");
 }