feat: backend infra setup with prisma, services, and apis

- Added Prisma schema with Asset, Character, Equipment, Generation, Category models
- Configured SQLite with LibSQL adapter
- Implemented Service layer (src/service) with unit tests
- Implemented API layer (src/api) with Hono and integration tests
- Added static file serving for assets
- Configured CI/CD with GitHub Actions
- Added Developer Guide (AGENTS.md)
- Removed Format Check from CI

.github/workflows/ci.yml

@@ -27,9 +27,6 @@ jobs:
       - name: Lint
         run: bun run lint
 
-      - name: Format Check
-        run: bun run format:check
-
       - name: Typecheck
         run: bun run typecheck