Enhance graph editor: fullscreen bg, add-entity focus, color picker fix, UI polish

- Move bg-anim canvas into graph container during fullscreen so dynamic background is visible
- Watch for new entity creation from graph add menu and auto-navigate to it after reload
- Position color picker at click coordinates instead of 0,0
- Replace test/preview play triangle with eye icon to distinguish from start/stop
- Always use port-aware bezier curves for edges instead of ELK routing
- Add fullscreen and add-entity buttons to toolbar with keyboard shortcuts (F11, +)
- Add confirmation dialog for relayout when manual positions exist
- Remove node body stroke, keep only color bar; add per-node color picker
- Clamp toolbar position on load to prevent off-screen drift
- Add graph tab to getting-started tutorial
- Add WASD/arrow spatial navigation, ESC reset, keyboard shortcuts

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

server/src/wled_controller/static/locales/zh.json

@@ -280,6 +280,7 @@
   "tour.dashboard": "仪表盘 — 实时查看运行中的目标、自动化和设备状态。",
   "tour.targets": "目标 — 添加 WLED 设备，配置 LED 目标的捕获设置和校准。",
   "tour.sources": "来源 — 管理捕获模板、图片来源、音频来源和色带。",
+  "tour.graph": "图表 — 所有实体及其连接的可视化概览。拖动端口进行连接，右键单击边线断开连接。",
   "tour.automations": "自动化 — 通过时间、音频或数值条件自动切换场景。",
   "tour.settings": "设置 — 备份和恢复配置，管理自动备份。",
   "tour.api": "API 文档 — 基于 Swagger 的交互式 REST API 文档。",
@@ -1402,5 +1403,9 @@
   "graph.connection_updated": "连接已更新",
   "graph.connection_failed": "更新连接失败",
   "graph.connection_removed": "连接已移除",
-  "graph.disconnect_failed": "断开连接失败"
+  "graph.disconnect_failed": "断开连接失败",
+  "graph.relayout_confirm": "重置所有手动节点位置并重新布局图表？",
+  "graph.fullscreen": "切换全屏",
+  "graph.add_entity": "添加实体",
+  "graph.color_picker": "节点颜色"
 }