feat(M5-004,M5-005,M5-006,M5-007): session-conversation binding, session:info broadcast, agent creation from TUI, and session metrics (#321)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/gateway/src/commands/command-executor-p8012.spec.ts

@@ -19,6 +19,8 @@ const mockRegistry = {
 
 const mockAgentService = {
   getSession: vi.fn(() => undefined),
+  applyAgentConfig: vi.fn(),
+  updateSessionModel: vi.fn(),
 };
 
 const mockSystemOverride = {
@@ -38,6 +40,33 @@ const mockRedis = {
   del: vi.fn(),
 };
 
+const mockAgentConfig = {
+  id: 'my-agent-id',
+  name: 'my-agent-id',
+  model: 'claude-sonnet-4-6',
+  provider: 'anthropic',
+  systemPrompt: null,
+  allowedTools: null,
+  isSystem: false,
+  ownerId: 'user-123',
+  status: 'idle',
+  createdAt: new Date(),
+  updatedAt: new Date(),
+};
+
+const mockBrain = {
+  agents: {
+    // findByName resolves with the agent when name matches, undefined otherwise
+    findByName: vi.fn((name: string) =>
+      Promise.resolve(name === 'my-agent-id' ? mockAgentConfig : undefined),
+    ),
+    findById: vi.fn((id: string) =>
+      Promise.resolve(id === 'my-agent-id' ? mockAgentConfig : undefined),
+    ),
+    create: vi.fn(),
+  },
+};
+
 function buildService(): CommandExecutorService {
   return new CommandExecutorService(
     mockRegistry as never,
@@ -45,6 +74,7 @@ function buildService(): CommandExecutorService {
     mockSystemOverride as never,
     mockSessionGC as never,
     mockRedis as never,
+    mockBrain as never,
     null,
     null,
   );