docs: reorganize docs into en/cn/ja folders

- Move documentation files into language-specific folders (en, cn, ja)
- Add Chinese and Japanese translations for all docs
- Extract Docker section from README to separate doc file
- Update README to link to new doc locations

docs/en/docker.md

@@ -0,0 +1,29 @@
+# Run with Docker
+
+If you just want to run it locally, the best way is to use Docker.
+
+First, install Docker if you haven't already: [Get Docker](https://docs.docker.com/get-docker/)
+
+Then run:
+
+```bash
+docker run -d -p 3000:3000 \
+  -e AI_PROVIDER=openai \
+  -e AI_MODEL=gpt-4o \
+  -e OPENAI_API_KEY=your_api_key \
+  ghcr.io/dayuanjiang/next-ai-draw-io:latest
+```
+
+Or use an env file:
+
+```bash
+cp env.example .env
+# Edit .env with your configuration
+docker run -d -p 3000:3000 --env-file .env ghcr.io/dayuanjiang/next-ai-draw-io:latest
+```
+
+Open [http://localhost:3000](http://localhost:3000) in your browser.
+
+Replace the environment variables with your preferred AI provider configuration. See [AI Providers](./ai-providers.md) for available options.
+
+> **Offline Deployment:** If `embed.diagrams.net` is blocked, see [Offline Deployment](./offline-deployment.md) for configuration options.