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-context.test.js

@@ -0,0 +1,79 @@
+const { PluginContext } = require('../src/plugins/plugin-context');
+const { EventBus } = require('../src/plugins/event-bus');
+
+describe('PluginContext', () => {
+  let context;
+  let mockDeps;
+
+  beforeEach(() => {
+    mockDeps = {
+      pluginId: 'test-plugin',
+      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() },
+      exportHooks: { preHooks: [], postHooks: [] }
+    };
+    context = new PluginContext(mockDeps);
+  });
+
+  test('exposes sidebar.registerPanel with namespaced id', () => {
+    const handler = jest.fn();
+    context.sidebar.registerPanel('my-panel', { icon: 'test', title: 'Test', render: handler });
+    expect(mockDeps.sidebar.registerPanel).toHaveBeenCalledWith('test-plugin:my-panel', { icon: 'test', title: 'Test', render: handler });
+  });
+
+  test('exposes commands.register with crash-safe wrapper', () => {
+    const badHandler = () => { throw new Error('boom'); };
+    context.commands.register('bad-cmd', 'Bad', badHandler, 'Ctrl+Alt+T');
+    const registeredHandler = mockDeps.commands.register.mock.calls[0][2];
+    expect(() => registeredHandler()).not.toThrow();
+  });
+
+  test('exposes settings.get/set scoped to plugin', () => {
+    context.settings.get('myKey');
+    context.settings.set('myKey', 'myValue');
+    expect(mockDeps.settings.get).toHaveBeenCalledWith('plugins.test-plugin.myKey');
+    expect(mockDeps.settings.set).toHaveBeenCalledWith('plugins.test-plugin.myKey', 'myValue');
+  });
+
+  test('exposes editor methods', () => {
+    context.editor.getContent();
+    context.editor.getSelection();
+    expect(mockDeps.editor.getContent).toHaveBeenCalled();
+    expect(mockDeps.editor.getSelection).toHaveBeenCalled();
+  });
+
+  test('exposes events via event bus', () => {
+    const handler = jest.fn();
+    context.events.on('test:event', handler);
+    context.events.emit('test:event', { data: 1 });
+    expect(handler).toHaveBeenCalledWith({ data: 1 });
+  });
+
+  test('exposes events.hasHandler', () => {
+    expect(context.events.hasHandler('no:such')).toBe(false);
+    context.events.on('exists:event', () => {});
+    expect(context.events.hasHandler('exists:event')).toBe(true);
+  });
+
+  test('exposes ipc.invoke', () => {
+    context.ipc.invoke('test:channel', { a: 1 });
+    expect(mockDeps.ipc.invoke).toHaveBeenCalledWith('test:channel', { a: 1 });
+  });
+
+  test('exposes exports.registerPreHook', () => {
+    const handler = jest.fn();
+    context.exports.registerPreHook(handler);
+    expect(mockDeps.exportHooks.preHooks).toContain(handler);
+  });
+
+  test('exposes exports.registerPostHook', () => {
+    const handler = jest.fn();
+    context.exports.registerPostHook(handler);
+    expect(mockDeps.exportHooks.postHooks).toContain(handler);
+  });
+});