feat: add review-work and ai-slop-remover as built-in skills, add remove-ai-slops command

Embed user-level skills into the plugin's built-in system so they ship
with the product rather than requiring per-user configuration.

- review-work: 5-agent parallel post-implementation review orchestrator
- ai-slop-remover: per-file AI-generated code smell detector and remover
- /remove-ai-slops: command that orchestrates parallel ai-slop-remover runs

src/features/builtin-skills/skills.ts

@@ -8,6 +8,8 @@ import {
   frontendUiUxSkill,
   gitMasterSkill,
   devBrowserSkill,
+  reviewWorkSkill,
+  aiSlopRemoverSkill,
 } from "./skills/index"
 
 export interface CreateBuiltinSkillsOptions {
@@ -27,7 +29,7 @@ export function createBuiltinSkills(options: CreateBuiltinSkillsOptions = {}): B
     browserSkill = playwrightSkill
   }
 
-  const skills = [browserSkill, frontendUiUxSkill, gitMasterSkill, devBrowserSkill]
+  const skills = [browserSkill, frontendUiUxSkill, gitMasterSkill, devBrowserSkill, reviewWorkSkill, aiSlopRemoverSkill]
 
   if (!disabledSkills) {
     return skills