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/padded-cell.ts

@@ -0,0 +1,59 @@
+import fs from "node:fs";
+import path from "node:path";
+import type { IdentityRegistry } from "./identity-registry.js";
+
+type EgoData = {
+  columns?: string[];
+  agentScope?: Record<string, Record<string, string>>;
+};
+
+/**
+ * Scan padded-cell's ego.json and upsert agent Discord IDs into the identity registry.
+ * Only runs if ego.json contains the "discord-id" column — otherwise treated as absent.
+ *
+ * @returns number of entries upserted, or -1 if padded-cell is not detected.
+ */
+export function scanPaddedCell(
+  registry: IdentityRegistry,
+  openclawDir: string,
+  logger: { info: (m: string) => void; warn: (m: string) => void },
+): number {
+  const egoPath = path.join(openclawDir, "ego.json");
+
+  if (!fs.existsSync(egoPath)) {
+    logger.info("dirigent: padded-cell ego.json not found — skipping auto-registration");
+    return -1;
+  }
+
+  let ego: EgoData;
+  try {
+    ego = JSON.parse(fs.readFileSync(egoPath, "utf8"));
+  } catch (e) {
+    logger.warn(`dirigent: failed to parse ego.json: ${String(e)}`);
+    return -1;
+  }
+
+  if (!Array.isArray(ego.columns) || !ego.columns.includes("discord-id")) {
+    logger.info('dirigent: ego.json does not have "discord-id" column — padded-cell not configured for Discord, skipping');
+    return -1;
+  }
+
+  const agentScope = ego.agentScope ?? {};
+  let count = 0;
+
+  for (const [agentId, fields] of Object.entries(agentScope)) {
+    const discordUserId = fields["discord-id"];
+    if (!discordUserId || typeof discordUserId !== "string") continue;
+
+    const existing = registry.findByAgentId(agentId);
+    registry.upsert({
+      agentId,
+      discordUserId,
+      agentName: existing?.agentName ?? agentId,
+    });
+    count++;
+  }
+
+  logger.info(`dirigent: padded-cell scan complete — upserted ${count} identity entries`);
+  return count;
+}