feat: add plugin marketplace renderer

tests/unit/project-plugin-service.test.ts

@@ -156,19 +156,32 @@ describe('ProjectPluginService', () => {
     await expect(service.readSelection(root)).resolves.toMatchObject({ enabledPluginIds: [] });
   });
 
-  it('rejects unknown plugin mutations but retains unknown IDs already in the file', async () => {
+  it('allows only explicit removal of a selected unknown ID and preserves every other ID', async () => {
     const root = await project();
     await writeFile(selectionPath(root), JSON.stringify({
       schemaVersion: 1,
-      enabledPluginIds: ['future.plugin'],
+      enabledPluginIds: ['future.plugin', 'another.future', 'makelore.data-service'],
       updatedAt: '2026-08-27T04:00:00.000Z',
     }), 'utf8');
     const service = new ProjectPluginService();
     await expect(service.enable(root, 'future.plugin')).rejects.toMatchObject({
       code: 'CODING_PLUGIN_UNKNOWN',
     });
-    await expect(service.enable(root, 'makelore.data-service')).resolves.toMatchObject({
-      enabledPluginIds: ['future.plugin', 'makelore.data-service'],
+    await expect(service.disable(root, 'future.plugin')).resolves.toMatchObject({
+      enabledPluginIds: ['another.future', 'makelore.data-service'],
+    });
+    const saved = JSON.parse(await readFile(selectionPath(root), 'utf8')) as { enabledPluginIds: string[] };
+    expect(saved).toMatchObject({
+      enabledPluginIds: ['another.future', 'makelore.data-service'],
     });
   });
+
+  it('rejects unselected unknown disable without writing a selection file', async () => {
+    const root = await project();
+    const service = new ProjectPluginService();
+    await expect(service.disable(root, 'future.plugin')).rejects.toMatchObject({
+      code: 'CODING_PLUGIN_UNKNOWN',
+    });
+    await expect(stat(selectionPath(root))).rejects.toMatchObject({ code: 'ENOENT' });
+  });
 });