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/features/tutorials.js

@@ -27,6 +27,7 @@ const gettingStartedSteps = [
     { selector: '#tab-btn-automations', textKey: 'tour.automations', position: 'bottom' },
     { selector: '#tab-btn-targets', textKey: 'tour.targets', position: 'bottom' },
     { selector: '#tab-btn-streams', textKey: 'tour.sources', position: 'bottom' },
+    { selector: '#tab-btn-graph', textKey: 'tour.graph', position: 'bottom' },
     { selector: 'a.header-link[href="/docs"]', textKey: 'tour.api', position: 'bottom' },
     { selector: '[onclick*="openCommandPalette"]', textKey: 'tour.search', position: 'bottom' },
     { selector: '[onclick*="toggleTheme"]', textKey: 'tour.theme', position: 'bottom' },