feat: agent-to-agent communication, dynamic agent creation, self-modification tools

Agent-to-agent: host routes messages with channel_type='agent' to target
agent's inbound.db, enriches with sender info, wakes target container.
Bidirectional routing works via inherited routing context.

Dynamic agents: create_agent MCP tool + system action handler creates
agent groups, folders, and optional CLAUDE.md on the fly.

Self-modification: install_packages (apt/npm, requires admin approval),
add_mcp_server (no approval), request_rebuild (builds per-agent-group
Docker image with approved packages). Approval flow reuses interactive
card infrastructure with pending_approvals table.

Also includes fixes from prior session: attachment download, reply context
extraction, message editing (platform message ID tracking), delivery retry
limits, and card update on button click.

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

src/db/db-v2.test.ts

@@ -62,7 +62,7 @@ describe('migrations', () => {
     const db = initTestDb();
     runMigrations(db);
     const row = db.prepare('SELECT MAX(version) as v FROM schema_version').get() as { v: number };
-    expect(row.v).toBe(2);
+    expect(row.v).toBe(3);
   });
 });
 

src/db/messaging-groups.ts

@@ -109,3 +109,14 @@ export function updateMessagingGroupAgent(
 export function deleteMessagingGroupAgent(id: string): void {
   getDb().prepare('DELETE FROM messaging_group_agents WHERE id = ?').run(id);
 }
+
+/** Get all messaging groups wired to an agent group (reverse lookup). */
+export function getMessagingGroupsByAgentGroup(agentGroupId: string): MessagingGroup[] {
+  return getDb()
+    .prepare(
+      `SELECT mg.* FROM messaging_groups mg
+       JOIN messaging_group_agents mga ON mga.messaging_group_id = mg.id
+       WHERE mga.agent_group_id = ?`,
+    )
+    .all(agentGroupId) as MessagingGroup[];
+}

src/db/migrations/003-pending-approvals.ts

@@ -0,0 +1,18 @@
+import type { Migration } from './index.js';
+
+export const migration003: Migration = {
+  version: 3,
+  name: 'pending-approvals',
+  up(db) {
+    db.exec(`
+      CREATE TABLE pending_approvals (
+        approval_id  TEXT PRIMARY KEY,
+        session_id   TEXT NOT NULL REFERENCES sessions(id),
+        request_id   TEXT NOT NULL,
+        action       TEXT NOT NULL,
+        payload      TEXT NOT NULL,
+        created_at   TEXT NOT NULL
+      );
+    `);
+  },
+};

src/db/migrations/index.ts

@@ -3,6 +3,7 @@ import type Database from 'better-sqlite3';
 import { log } from '../../log.js';
 import { migration001 } from './001-initial.js';
 import { migration002 } from './002-chat-sdk-state.js';
+import { migration003 } from './003-pending-approvals.js';
 
 export interface Migration {
   version: number;
@@ -10,7 +11,7 @@ export interface Migration {
   up: (db: Database.Database) => void;
 }
 
-const migrations: Migration[] = [migration001, migration002];
+const migrations: Migration[] = [migration001, migration002, migration003];
 
 export function runMigrations(db: Database.Database): void {
   db.exec(`

src/db/schema.ts

@@ -93,11 +93,13 @@ CREATE TABLE messages_in (
   content        TEXT NOT NULL
 );
 
--- Host tracks which messages_out IDs have been delivered.
+-- Host tracks delivery outcomes for messages_out IDs.
 -- Avoids writing to outbound.db (container-owned).
 CREATE TABLE delivered (
-  message_out_id TEXT PRIMARY KEY,
-  delivered_at   TEXT NOT NULL
+  message_out_id      TEXT PRIMARY KEY,
+  platform_message_id TEXT,
+  status              TEXT NOT NULL DEFAULT 'delivered',
+  delivered_at        TEXT NOT NULL
 );
 `;
 

src/db/sessions.ts

@@ -1,4 +1,4 @@
-import type { PendingQuestion, Session } from '../types.js';
+import type { PendingApproval, PendingQuestion, Session } from '../types.js';
 import { getDb } from './connection.js';
 
 // ── Sessions ──
@@ -90,3 +90,24 @@ export function getPendingQuestion(questionId: string): PendingQuestion | undefi
 export function deletePendingQuestion(questionId: string): void {
   getDb().prepare('DELETE FROM pending_questions WHERE question_id = ?').run(questionId);
 }
+
+// ── Pending Approvals ──
+
+export function createPendingApproval(pa: PendingApproval): void {
+  getDb()
+    .prepare(
+      `INSERT INTO pending_approvals (approval_id, session_id, request_id, action, payload, created_at)
+       VALUES (@approval_id, @session_id, @request_id, @action, @payload, @created_at)`,
+    )
+    .run(pa);
+}
+
+export function getPendingApproval(approvalId: string): PendingApproval | undefined {
+  return getDb().prepare('SELECT * FROM pending_approvals WHERE approval_id = ?').get(approvalId) as
+    | PendingApproval
+    | undefined;
+}
+
+export function deletePendingApproval(approvalId: string): void {
+  getDb().prepare('DELETE FROM pending_approvals WHERE approval_id = ?').run(approvalId);
+}