feat: wire multi-agent config and routing

Co-authored-by: Mark Pors <1078320+pors@users.noreply.github.com>

src/discord/monitor.ts

@@ -17,6 +17,7 @@ import { GatewayIntents, GatewayPlugin } from "@buape/carbon/gateway";
 import type { APIAttachment } from "discord-api-types/v10";
 import { ApplicationCommandOptionType, Routes } from "discord-api-types/v10";
 
+import { resolveAckReaction } from "../agents/identity.js";
 import { resolveTextChunkLimit } from "../auto-reply/chunk.js";
 import { hasControlCommand } from "../auto-reply/command-detection.js";
 import {
@@ -501,7 +502,6 @@ export function createDiscordMessageHandler(params: {
     guildEntries,
   } = params;
   const logger = getChildLogger({ module: "discord-auto-reply" });
-  const ackReaction = (cfg.messages?.ackReaction ?? "").trim();
   const ackReactionScope = cfg.messages?.ackReactionScope ?? "group-mentions";
   const groupPolicy = discordConfig?.groupPolicy ?? "open";
 
@@ -842,6 +842,7 @@ export function createDiscordMessageHandler(params: {
         logVerbose(`discord: drop message ${message.id} (empty content)`);
         return;
       }
+      const ackReaction = resolveAckReaction(cfg, route.agentId);
       const shouldAckReaction = () => {
         if (!ackReaction) return false;
         if (ackReactionScope === "all") return true;