Initial commit: Phase 1 scaffolding complete

- Root package.json with concurrently for dev server
- Client: Vite + React 18 with design tokens and proxy config
- Server: Express with CORS, multer (20MB), Sharp resize
- Upload endpoint with preview generation
- Dockerfile (multi-stage) and docker-compose.yml
- Canvas deferred to Phase 8 (export functionality)

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

.dockerignore

@@ -0,0 +1,12 @@
+node_modules
+npm-debug.log
+.git
+.gitignore
+*.md
+.DS_Store
+uploads/*
+!uploads/.gitkeep
+exports/*
+!exports/.gitkeep
+dist
+.cache