feat: v1.1.0 - Docker, i18n, setup wizard, rate limiting, OpenAPI

New features:
- Docker support (Dockerfile + docker-compose.yml)
- GitHub Actions CI pipeline (PHP lint, JS lint, Docker build, i18n validation)
- Internationalization system with 3 languages (it, en, de) and 347 translation keys
- First-run setup wizard (4-step configuration)
- File-based API rate limiting (120/15/5 req/min tiers)
- OpenAPI 3.1.0 specification for all 43 API endpoints
- CONTRIBUTING.md with translation and development guide
- Screenshots directory placeholder

Modified:
- README.md: Docker badges, install instructions, translations section
- api/index.php: rate limiting middleware
- assets/js/app.js: i18n system, setup wizard, t() function
- assets/css/style.css: setup wizard styles
- index.html: data-i18n attributes, setup wizard overlay, language settings
- .gitignore: rate_limits exclusion

.dockerignore

@@ -0,0 +1,34 @@
+# Docker runtime files
+data/dispensa.db
+data/*.db-wal
+data/*.db-shm
+data/backups/
+data/cron.log
+data/smart_shopping_cache.json
+data/bring_token.json
+data/bring_catalog.json
+data/dupliclick_token.json
+data/client_debug.log
+data/*.crt
+data/*.pem
+
+# Config (mounted as volume)
+.env
+
+# Git
+.git
+.gitignore
+
+# Docs (not needed in container)
+README.md
+CHANGELOG.md
+CONTRIBUTING.md
+LICENSE
+docs/
+*.md
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo