feat: add plugin marketplace renderer

electron/coding-plugins/project-service.ts

@@ -286,14 +286,14 @@ export class ProjectPluginService {
         );
       }
       const knownIds = knownPluginIdSet(this.options.knownPluginIds);
-      if (!knownIds.has(id)) {
+      const current = await this.readSelection(normalizedProjectPath);
+      const wasEnabled = current.enabledPluginIds.includes(id);
+      if (!knownIds.has(id) && (enabled || !wasEnabled)) {
         throw new ProjectPluginServiceError(
           'CODING_PLUGIN_UNKNOWN',
           `Unknown coding plugin: ${id}`,
         );
       }
-      const current = await this.readSelection(normalizedProjectPath);
-      const wasEnabled = current.enabledPluginIds.includes(id);
       // A missing read is intentionally side-effect free.  A real state
       // change (or the legacy projection) is the user mutation that creates
       // the selection file.