feat(gateway): MosaicPlugin lifecycle + ReloadService + hot reload (P8-013) (#182)

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

apps/gateway/src/reload/reload.service.spec.ts

@@ -0,0 +1,106 @@
+import { describe, expect, it, vi } from 'vitest';
+import { ReloadService } from './reload.service.js';
+
+function createMockCommandRegistry() {
+  return {
+    getManifest: vi.fn().mockReturnValue({
+      version: 1,
+      commands: [],
+      skills: [],
+    }),
+  };
+}
+
+function createService() {
+  const registry = createMockCommandRegistry();
+  const service = new ReloadService(registry as never);
+  return { service, registry };
+}
+
+describe('ReloadService', () => {
+  it('reload() calls onUnload then onLoad for registered MosaicPlugin', async () => {
+    const { service } = createService();
+
+    const callOrder: string[] = [];
+    const mockPlugin = {
+      pluginName: 'test-plugin',
+      onLoad: vi.fn().mockImplementation(() => {
+        callOrder.push('onLoad');
+        return Promise.resolve();
+      }),
+      onUnload: vi.fn().mockImplementation(() => {
+        callOrder.push('onUnload');
+        return Promise.resolve();
+      }),
+    };
+
+    service.registerPlugin('test-plugin', mockPlugin);
+    const result = await service.reload('command');
+
+    expect(mockPlugin.onUnload).toHaveBeenCalledOnce();
+    expect(mockPlugin.onLoad).toHaveBeenCalledOnce();
+    expect(callOrder).toEqual(['onUnload', 'onLoad']);
+    expect(result.message).toContain('test-plugin');
+  });
+
+  it('reload() continues if one plugin throws during onUnload', async () => {
+    const { service } = createService();
+
+    const badPlugin = {
+      pluginName: 'bad-plugin',
+      onLoad: vi.fn().mockResolvedValue(undefined),
+      onUnload: vi.fn().mockRejectedValue(new Error('unload failed')),
+    };
+
+    service.registerPlugin('bad-plugin', badPlugin);
+    const result = await service.reload('command');
+
+    expect(result.message).toContain('bad-plugin');
+    expect(result.message).toContain('unload failed');
+  });
+
+  it('reload() skips non-MosaicPlugin objects', async () => {
+    const { service } = createService();
+
+    const notAPlugin = { foo: 'bar' };
+    service.registerPlugin('not-a-plugin', notAPlugin);
+
+    // Should not throw
+    const result = await service.reload('command');
+    expect(result).toBeDefined();
+    expect(result.message).not.toContain('not-a-plugin');
+  });
+
+  it('reload() returns SystemReloadPayload with commands, skills, providers, message', async () => {
+    const { service, registry } = createService();
+    registry.getManifest.mockReturnValue({
+      version: 1,
+      commands: [
+        {
+          name: 'test',
+          description: 'test cmd',
+          aliases: [],
+          scope: 'core',
+          execution: 'socket',
+          available: true,
+        },
+      ],
+      skills: [],
+    });
+
+    const result = await service.reload('rest');
+
+    expect(result).toHaveProperty('commands');
+    expect(result).toHaveProperty('skills');
+    expect(result).toHaveProperty('providers');
+    expect(result).toHaveProperty('message');
+    expect(result.commands).toHaveLength(1);
+  });
+
+  it('registerPlugin() logs plugin registration', () => {
+    const { service } = createService();
+
+    // Should not throw and should register
+    expect(() => service.registerPlugin('my-plugin', {})).not.toThrow();
+  });
+});