feat: rewrite plugin as v2 with globalThis-based turn management

Complete rewrite of the Dirigent plugin turn management system to work
correctly with OpenClaw's VM-context-per-session architecture:

- All turn state stored on globalThis (persists across VM context hot-reloads)
- Hooks registered unconditionally on every api instance; event-level dedup
  (runId Set for agent_end, WeakSet for before_model_resolve) prevents
  double-processing
- Gateway lifecycle events (gateway_start/stop) guarded once via globalThis flag
- Shared initializingChannels lock prevents concurrent channel init across VM
  contexts in message_received and before_model_resolve
- New ChannelStore and IdentityRegistry replace old policy/session-state modules
- Added agent_end hook with tail-match polling for Discord delivery confirmation
- Added web control page, padded-cell auto-scan, discussion tool support
- Removed obsolete v1 modules: channel-resolver, channel-modes, discussion-service,
  session-state, turn-bootstrap, policy/store, rules, decision-input

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugin/core/mentions.ts

@@ -1,5 +1,3 @@
-import type { DirigentConfig } from "../rules.js";
-
 function userIdFromToken(token: string): string | undefined {
   try {
     const segment = token.split(".")[0];
@@ -25,7 +23,7 @@ export function extractMentionedUserIds(content: string): string[] {
   return ids;
 }
 
-export function getModeratorUserId(config: DirigentConfig): string | undefined {
-  if (!config.moderatorBotToken) return undefined;
-  return userIdFromToken(config.moderatorBotToken);
+export function getModeratorUserIdFromToken(token: string | undefined): string | undefined {
+  if (!token) return undefined;
+  return userIdFromToken(token);
 }