feat: Expand fleet to 23 skills across all domains

New skills (14):
- nestjs-best-practices: 40 priority-ranked rules (kadajett)
- fastapi: Pydantic v2, async SQLAlchemy, JWT auth (jezweb)
- architecture-patterns: Clean Architecture, Hexagonal, DDD (wshobson)
- python-performance-optimization: Profiling and optimization (wshobson)
- ai-sdk: Vercel AI SDK streaming and agent patterns (vercel)
- create-agent: Modular agent architecture with OpenRouter (openrouterteam)
- proactive-agent: WAL Protocol, compaction recovery, self-improvement (halthelobster)
- brand-guidelines: Brand identity enforcement (anthropics)
- ui-animation: Motion design with accessibility (mblode)
- marketing-ideas: 139 ideas across 14 categories (coreyhaines31)
- pricing-strategy: SaaS pricing and tier design (coreyhaines31)
- programmatic-seo: SEO at scale with playbooks (coreyhaines31)
- competitor-alternatives: Comparison page architecture (coreyhaines31)
- referral-program: Referral and affiliate programs (coreyhaines31)

README reorganized by domain: Code Quality, Frontend, Backend,
Auth, AI/Agent Building, Marketing, Design, Meta.

Mosaic Stack is not limited to coding — the Orchestrator serves
coding, business, design, marketing, writing, logistics, and analysis.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

skills/nestjs-best-practices/rules/di-scope-awareness.md

@@ -0,0 +1,94 @@
+---
+title: Understand Provider Scopes
+impact: CRITICAL
+impactDescription: Prevents data leaks and performance issues
+tags: dependency-injection, scopes, request-context
+---
+
+## Understand Provider Scopes
+
+NestJS has three provider scopes: DEFAULT (singleton), REQUEST (per-request instance), and TRANSIENT (new instance for each injection). Most providers should be singletons. Request-scoped providers have performance implications as they bubble up through the dependency tree. Understanding scopes prevents memory leaks and incorrect data sharing.
+
+**Incorrect (wrong scope usage):**
+
+```typescript
+// Request-scoped when not needed (performance hit)
+@Injectable({ scope: Scope.REQUEST })
+export class UsersService {
+  // This creates a new instance for EVERY request
+  // All dependencies also become request-scoped
+  async findAll() {
+    return this.userRepo.find();
+  }
+}
+
+// Singleton with mutable request state
+@Injectable() // Default: singleton
+export class RequestContextService {
+  private userId: string; // DANGER: Shared across all requests!
+
+  setUser(userId: string) {
+    this.userId = userId; // Overwrites for all concurrent requests
+  }
+
+  getUser() {
+    return this.userId; // Returns wrong user!
+  }
+}
+```
+
+**Correct (appropriate scope for each use case):**
+
+```typescript
+// Singleton for stateless services (default, most common)
+@Injectable()
+export class UsersService {
+  constructor(private readonly userRepo: UserRepository) {}
+
+  async findById(id: string): Promise<User> {
+    return this.userRepo.findOne({ where: { id } });
+  }
+}
+
+// Request-scoped ONLY when you need request context
+@Injectable({ scope: Scope.REQUEST })
+export class RequestContextService {
+  private userId: string;
+
+  setUser(userId: string) {
+    this.userId = userId;
+  }
+
+  getUser(): string {
+    return this.userId;
+  }
+}
+
+// Better: Use NestJS built-in request context
+import { REQUEST } from '@nestjs/core';
+import { Request } from 'express';
+
+@Injectable({ scope: Scope.REQUEST })
+export class AuditService {
+  constructor(@Inject(REQUEST) private request: Request) {}
+
+  log(action: string) {
+    console.log(`User ${this.request.user?.id} performed ${action}`);
+  }
+}
+
+// Best: Use ClsModule for async context (no scope bubble-up)
+import { ClsService } from 'nestjs-cls';
+
+@Injectable() // Stays singleton!
+export class AuditService {
+  constructor(private cls: ClsService) {}
+
+  log(action: string) {
+    const userId = this.cls.get('userId');
+    console.log(`User ${userId} performed ${action}`);
+  }
+}
+```
+
+Reference: [NestJS Injection Scopes](https://docs.nestjs.com/fundamentals/injection-scopes)