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

src/channels/slack/adapter.ts

@@ -16,6 +16,7 @@ import type {
   ChannelStatus,
 } from '../types.js';
 import { splitMessage } from '../utils.js';
+import type { PairingManager } from '../pairing.js';
 
 /** Configuration for the Slack channel adapter. */
 export interface SlackAdapterConfig {
@@ -26,6 +27,8 @@ export interface SlackAdapterConfig {
   allowedChannelIds?: string[];
   /** Require bot mention to respond (default: false). */
   requireMention?: boolean;
+  /** Optional pairing manager for DM pairing codes. */
+  pairingManager?: PairingManager;
 }
 
 /** Minimal shape of a Slack message event from Bolt. */
@@ -275,7 +278,32 @@ export class SlackAdapter implements ChannelAdapter {
       this.config.allowedChannelIds.length > 0 &&
       !this.config.allowedChannelIds.includes(channelId)
     ) {
-      return;
+      // Pairing fallback — check if the Slack user is approved or sending a valid code
+      const pm = this.config.pairingManager;
+      const userId = message.user;
+      if (pm?.enabled && userId) {
+        if (pm.isApproved('slack', userId)) {
+          // Approved — fall through to normal message handling
+        } else {
+          const text = (message.text ?? '').trim();
+          if (text && pm.validateCode('slack', userId, text)) {
+            // Code validated — send confirmation via Slack
+            if (this.app) {
+              const threadTs = message.thread_ts ?? message.ts ?? '';
+              try {
+                await this.app.client.chat.postMessage({
+                  channel: channelId,
+                  text: 'Pairing successful! You can now chat with Flynn.',
+                  thread_ts: threadTs || undefined,
+                });
+              } catch { /* ignore send errors */ }
+            }
+          }
+          return;
+        }
+      } else {
+        return;
+      }
     }
 
     // Mention requirement