feat: add AgentRouter for config-based sender/channel routing

src/agents/router.test.ts

@@ -0,0 +1,72 @@
+import { describe, it, expect } from 'vitest';
+import { AgentRouter } from './router.js';
+import type { RoutingConfig } from '../config/schema.js';
+
+describe('AgentRouter', () => {
+  describe('resolve()', () => {
+    it('returns default_agent when no specific match', () => {
+      const router = new AgentRouter({
+        default_agent: 'assistant',
+        channels: {},
+        senders: {},
+      });
+      expect(router.resolve('telegram', '12345')).toBe('assistant');
+    });
+
+    it('returns undefined when no default and no match', () => {
+      const router = new AgentRouter({
+        channels: {},
+        senders: {},
+      });
+      expect(router.resolve('telegram', '12345')).toBeUndefined();
+    });
+
+    it('matches exact sender', () => {
+      const router = new AgentRouter({
+        default_agent: 'assistant',
+        channels: {},
+        senders: { 'telegram:12345': 'coder' },
+      });
+      expect(router.resolve('telegram', '12345')).toBe('coder');
+    });
+
+    it('matches sender with glob pattern', () => {
+      const router = new AgentRouter({
+        default_agent: 'assistant',
+        channels: {},
+        senders: { 'slack:U0*': 'coder' },
+      });
+      expect(router.resolve('slack', 'U0ABC')).toBe('coder');
+    });
+
+    it('matches channel when no sender match', () => {
+      const router = new AgentRouter({
+        default_agent: 'assistant',
+        channels: { discord: 'coder' },
+        senders: {},
+      });
+      expect(router.resolve('discord', 'any-user')).toBe('coder');
+    });
+
+    it('sender match takes priority over channel match', () => {
+      const router = new AgentRouter({
+        default_agent: 'assistant',
+        channels: { discord: 'coder' },
+        senders: { 'discord:special-user': 'vip' },
+      });
+      expect(router.resolve('discord', 'special-user')).toBe('vip');
+      expect(router.resolve('discord', 'normal-user')).toBe('coder');
+    });
+
+    it('falls through: sender -> channel -> default', () => {
+      const router = new AgentRouter({
+        default_agent: 'fallback',
+        channels: { discord: 'guild-agent' },
+        senders: { 'discord:admin': 'admin-agent' },
+      });
+      expect(router.resolve('discord', 'admin')).toBe('admin-agent');
+      expect(router.resolve('discord', 'regular')).toBe('guild-agent');
+      expect(router.resolve('telegram', 'someone')).toBe('fallback');
+    });
+  });
+});