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/fastapi/templates/src/database.py

@@ -0,0 +1,36 @@
+"""Database configuration with async SQLAlchemy 2.0."""
+
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.orm import DeclarativeBase
+
+from src.config import settings
+
+# Create async engine
+engine = create_async_engine(
+    settings.DATABASE_URL,
+    echo=settings.DEBUG,
+)
+
+# Session factory
+async_session = async_sessionmaker(
+    engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+)
+
+
+class Base(DeclarativeBase):
+    """Base class for all SQLAlchemy models."""
+
+    pass
+
+
+async def get_db():
+    """Dependency that provides a database session."""
+    async with async_session() as session:
+        try:
+            yield session
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            raise