fix(slack): add reactionNotifications config check to reactions handler

The Slack reactions handler was processing all reactions unconditionally,
ignoring the reactionNotifications config setting.

This adds the same filtering logic that exists in Telegram/Discord/Signal:
- Check reactionMode config (off/own/all/allowlist)
- Skip bot's own reactions
- For 'own' mode, only process reactions on messages sent by the bot
- For 'allowlist' mode, only process reactions from allowlisted users

Fixes reactions not being routed to agent sessions when configured.

src/slack/monitor/events/reactions.ts

@@ -12,6 +12,26 @@ export function registerSlackReactionEvents(params: { ctx: SlackMonitorContext }
 
   const handleReactionEvent = async (event: SlackReactionEvent, action: string) => {
     try {
+      // Check reactionNotifications config (consistent with Telegram/Discord/Signal)
+      const reactionMode = ctx.reactionMode ?? "own";
+      if (reactionMode === "off") return;
+
+      // Skip bot reactions (consistent with other providers)
+      if (event.user === ctx.botUserId) return;
+
+      // For "own" mode, only process reactions on messages sent by this bot
+      if (reactionMode === "own" && event.item_user !== ctx.botUserId) return;
+
+      // For "allowlist" mode, only process reactions from allowlisted users
+      if (reactionMode === "allowlist") {
+        const allowlist = ctx.reactionAllowlist ?? [];
+        if (allowlist.length === 0) return;
+        const userAllowed = allowlist.some(
+          (entry) => String(entry).toLowerCase() === String(event.user).toLowerCase(),
+        );
+        if (!userAllowed) return;
+      }
+
       const item = event.item;
       if (!item || item.type !== "message") return;