feat: scaffold monorepo with shared types and NestJS server

- pnpm workspace with packages/app, packages/server, packages/shared
- @mp-pilates/shared: enums, constants, TypeScript interfaces for all 8 data models
- @mp-pilates/server: NestJS bootstrap with health check, validation pipe, CORS
- Base TypeScript config with strict mode

.gitignore

@@ -0,0 +1,41 @@
+# Dependencies
+node_modules/
+
+# Build output
+dist/
+dist-ssr/
+
+# Environment
+.env
+.env.local
+.env.*.local
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log
+npm-debug.log*
+pnpm-debug.log*
+
+# Test coverage
+coverage/
+
+# Prisma
+packages/server/prisma/*.db
+packages/server/prisma/migrations/**/migration_lock.toml
+
+# uni-app build
+packages/app/dist/
+packages/app/unpackage/
+
+# Misc
+*.tgz
+.cache/