feat(plugins): add PluginContext, PluginRegistry, and SettingsStore

- PluginContext: scoped API with crash-safe command wrappers
- PluginRegistry: lifecycle management with graceful init failure
- SettingsStore: plugin-scoped key/value via IPC backend
- Export hooks: pre/post hooks on registry for cross-plugin integration

Amit Haridas

tests/plugin-registry.test.js

@@ -0,0 +1,87 @@
+const { PluginRegistry } = require('../src/plugins/plugin-registry');
+const { PluginAPI } = require('../src/plugins/plugin-api');
+const { EventBus } = require('../src/plugins/event-bus');
+
+class TestPlugin extends PluginAPI {
+  init(context) { this.initialized = true; this.ctx = context; }
+  activate() { this.activated = true; }
+  deactivate() { this.deactivated = true; }
+}
+
+describe('PluginRegistry', () => {
+  let registry;
+  let mockDeps;
+
+  beforeEach(() => {
+    mockDeps = {
+      sidebar: { registerPanel: jest.fn() },
+      commands: { register: jest.fn() },
+      statusBar: { registerIndicator: jest.fn() },
+      eventBus: new EventBus(),
+      settings: { get: jest.fn(), set: jest.fn(), onChanged: jest.fn() },
+      editor: { getContent: jest.fn(() => ''), getSelection: jest.fn(() => ''), insertAtCursor: jest.fn(), onContentChanged: jest.fn() },
+      ipc: { invoke: jest.fn(), on: jest.fn() }
+    };
+    registry = new PluginRegistry(mockDeps);
+  });
+
+  test('register — stores plugin and calls init', () => {
+    registry.register({
+      id: 'test', name: 'Test', version: '1.0.0', description: 'desc',
+      manifest: {}, PluginClass: TestPlugin, dir: '/tmp/test'
+    });
+    const entry = registry.getPlugin('test');
+    expect(entry).toBeDefined();
+    expect(entry.instance.initialized).toBe(true);
+  });
+
+  test('register — works without PluginClass', () => {
+    registry.register({
+      id: 'manifest-only', name: 'Manifest Only', version: '1.0.0', description: 'desc',
+      manifest: {}, PluginClass: null, dir: '/tmp/test'
+    });
+    expect(registry.getPlugin('manifest-only')).toBeDefined();
+  });
+
+  test('register — init error does not crash, plugin not registered', () => {
+    class BadPlugin extends PluginAPI {
+      init() { throw new Error('init fail'); }
+    }
+    expect(() => {
+      registry.register({
+        id: 'bad', name: 'Bad', version: '1.0.0', description: 'desc',
+        manifest: {}, PluginClass: BadPlugin, dir: '/tmp/test'
+      });
+    }).not.toThrow();
+    expect(registry.getPlugin('bad')).toBeUndefined();
+  });
+
+  test('getPlugin — returns undefined for unknown', () => {
+    expect(registry.getPlugin('nope')).toBeUndefined();
+  });
+
+  test('getAll — returns all registered plugins', () => {
+    registry.register({ id: 'a', name: 'A', version: '1', description: '', manifest: {}, PluginClass: null, dir: '' });
+    registry.register({ id: 'b', name: 'B', version: '1', description: '', manifest: {}, PluginClass: null, dir: '' });
+    expect(registry.getAll()).toHaveLength(2);
+  });
+
+  test('activate — calls activate on plugin instance', () => {
+    registry.register({ id: 'test', name: 'Test', version: '1', description: '', manifest: {}, PluginClass: TestPlugin, dir: '' });
+    registry.activate('test');
+    expect(registry.getPlugin('test').instance.activated).toBe(true);
+  });
+
+  test('deactivate — calls deactivate on plugin instance', () => {
+    registry.register({ id: 'test', name: 'Test', version: '1', description: '', manifest: {}, PluginClass: TestPlugin, dir: '' });
+    registry.deactivate('test');
+    expect(registry.getPlugin('test').instance.deactivated).toBe(true);
+  });
+
+  test('exportHooks are available and populated', () => {
+    registry.register({ id: 'test', name: 'Test', version: '1', description: '', manifest: {}, PluginClass: TestPlugin, dir: '' });
+    const handler = jest.fn();
+    registry.getPlugin('test').instance.ctx.exports.registerPreHook(handler);
+    expect(registry.exportHooks.preHooks).toContain(handler);
+  });
+});