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/js/app.js

@@ -162,6 +162,7 @@ import {
     loadGraphEditor, openGraphSearch, closeGraphSearch,
     toggleGraphLegend, toggleGraphMinimap,
     graphFitAll, graphZoomIn, graphZoomOut, graphRelayout,
+    graphToggleFullscreen, graphAddEntity,
 } from './features/graph-editor.js';
 
 // Layer 6: tabs, navigation, command palette, settings
@@ -472,6 +473,8 @@ Object.assign(window, {
     graphZoomIn,
     graphZoomOut,
     graphRelayout,
+    graphToggleFullscreen,
+    graphAddEntity,
 
     // tabs / navigation / command palette
     switchTab,