feat(v2): track unregistered senders + setup improvements

- Add unregistered_senders table to capture dropped message origins
  (one row per sender, upserted with message_count and last_seen)
- Add inbound DM logging to chat-sdk-bridge for debugging
- Add vercel CLI to base container image
- Install vercel-cli and frontend-engineer container skills
- Default requiresTrigger to false in register step

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/db/dropped-messages.ts

@@ -0,0 +1,44 @@
+import { getDb } from './connection.js';
+
+export interface UnregisteredSender {
+  channel_type: string;
+  platform_id: string;
+  user_id: string | null;
+  sender_name: string | null;
+  reason: string;
+  messaging_group_id: string | null;
+  agent_group_id: string | null;
+  message_count: number;
+  first_seen: string;
+  last_seen: string;
+}
+
+export function recordDroppedMessage(msg: {
+  channel_type: string;
+  platform_id: string;
+  user_id: string | null;
+  sender_name: string | null;
+  reason: string;
+  messaging_group_id: string | null;
+  agent_group_id: string | null;
+}): void {
+  const now = new Date().toISOString();
+  getDb()
+    .prepare(
+      `INSERT INTO unregistered_senders (channel_type, platform_id, user_id, sender_name, reason, messaging_group_id, agent_group_id, message_count, first_seen, last_seen)
+       VALUES (@channel_type, @platform_id, @user_id, @sender_name, @reason, @messaging_group_id, @agent_group_id, 1, @now, @now)
+       ON CONFLICT (channel_type, platform_id) DO UPDATE SET
+         user_id = COALESCE(excluded.user_id, unregistered_senders.user_id),
+         sender_name = COALESCE(excluded.sender_name, unregistered_senders.sender_name),
+         reason = excluded.reason,
+         message_count = unregistered_senders.message_count + 1,
+         last_seen = excluded.last_seen`,
+    )
+    .run({ ...msg, now });
+}
+
+export function getUnregisteredSenders(limit = 50): UnregisteredSender[] {
+  return getDb()
+    .prepare('SELECT * FROM unregistered_senders ORDER BY last_seen DESC LIMIT ?')
+    .all(limit) as UnregisteredSender[];
+}

src/db/migrations/008-dropped-messages.ts

@@ -0,0 +1,27 @@
+import type Database from 'better-sqlite3';
+import type { Migration } from './index.js';
+
+export const migration008: Migration = {
+  version: 8,
+  name: 'dropped-messages',
+  up: (db: Database.Database) => {
+    db.exec(`
+      CREATE TABLE IF NOT EXISTS unregistered_senders (
+        channel_type    TEXT NOT NULL,
+        platform_id     TEXT NOT NULL,
+        user_id         TEXT,
+        sender_name     TEXT,
+        reason          TEXT NOT NULL,
+        messaging_group_id TEXT,
+        agent_group_id  TEXT,
+        message_count   INTEGER NOT NULL DEFAULT 1,
+        first_seen      TEXT NOT NULL,
+        last_seen       TEXT NOT NULL,
+        PRIMARY KEY (channel_type, platform_id)
+      );
+
+      CREATE INDEX IF NOT EXISTS idx_unregistered_senders_last_seen
+        ON unregistered_senders(last_seen);
+    `);
+  },
+};

src/db/migrations/index.ts

@@ -7,6 +7,7 @@ import { migration003 } from './003-pending-approvals.js';
 import { migration004 } from './004-agent-destinations.js';
 import { migration005 } from './005-pending-credentials.js';
 import { migration007 } from './007-pending-approvals-title-options.js';
+import { migration008 } from './008-dropped-messages.js';
 
 export interface Migration {
   version: number;
@@ -14,7 +15,7 @@ export interface Migration {
   up: (db: Database.Database) => void;
 }
 
-const migrations: Migration[] = [migration001, migration002, migration003, migration004, migration005, migration007];
+const migrations: Migration[] = [migration001, migration002, migration003, migration004, migration005, migration007, migration008];
 
 export function runMigrations(db: Database.Database): void {
   db.exec(`