chore: remove dead code (pairedCursorKey, unused ARBITER_AGENT_TYPE import)

src/message-runtime-rules.ts

@@ -31,14 +31,6 @@ export function advanceLastAgentCursor(
   saveState();
 }
 
-/** Returns the cursor key for a paired room role. */
-export function pairedCursorKey(
-  chatJid: string,
-  isReviewerTurn: boolean,
-): string {
-  return isReviewerTurn ? `${chatJid}:reviewer` : chatJid;
-}
-
 /** Map task status to the active role. */
 export function resolveActiveRole(
   taskStatus?: string | null,

src/message-runtime.ts

@@ -21,7 +21,6 @@ import {
   type WorkItem,
 } from './db.js';
 import {
-  ARBITER_AGENT_TYPE,
   CLAUDE_SERVICE_ID,
   CODEX_MAIN_SERVICE_ID,
   CODEX_REVIEW_SERVICE_ID,