feat: complete DM pairing codes with channel adapters, gateway handlers, and TUI command (Tier 4 feature 4)

src/gateway/handlers/pairing.ts

@@ -0,0 +1,42 @@
+import type { GatewayRequest, OutboundMessage } from '../protocol.js';
+import { makeResponse, makeError, ErrorCode } from '../protocol.js';
+import type { PairingManager } from '../../channels/pairing.js';
+
+export interface PairingHandlerDeps {
+  pairingManager: PairingManager;
+}
+
+export function createPairingHandlers(deps: PairingHandlerDeps) {
+  return {
+    'pairing.generate': async (request: GatewayRequest): Promise<OutboundMessage> => {
+      const label = request.params?.label as string | undefined;
+      const code = deps.pairingManager.generateCode(label);
+      const pending = deps.pairingManager.listPendingCodes();
+      const entry = pending.find(p => p.code === code);
+
+      return makeResponse(request.id, {
+        code,
+        expiresAt: entry?.expiresAt ?? null,
+      });
+    },
+
+    'pairing.list': async (request: GatewayRequest): Promise<OutboundMessage> => {
+      return makeResponse(request.id, {
+        pending: deps.pairingManager.listPendingCodes(),
+        approved: deps.pairingManager.listApproved(),
+      });
+    },
+
+    'pairing.revoke': async (request: GatewayRequest): Promise<OutboundMessage> => {
+      const channel = request.params?.channel as string | undefined;
+      const senderId = request.params?.senderId as string | undefined;
+
+      if (!channel || !senderId) {
+        return makeError(request.id, ErrorCode.InvalidRequest, 'Missing required params: channel, senderId');
+      }
+
+      const revoked = deps.pairingManager.revokeApproval(channel, senderId);
+      return makeResponse(request.id, { revoked });
+    },
+  };
+}