✨ feat: add dependency graph view for task visualization

Add a new interactive graph view alongside the kanban board for visualizing
task dependencies. The graph view uses React Flow with dagre auto-layout to
display tasks as nodes connected by dependency edges.

Key features:
- Toggle between kanban and graph view via new control buttons
- Custom TaskNode component matching existing card styling/themes
- Animated edges that flow when tasks are in progress
- Status-aware node colors (backlog, in-progress, waiting, verified)
- Blocked tasks show lock icon with dependency count tooltip
- MiniMap for navigation in large graphs
- Zoom, pan, fit-view, and lock controls
- Horizontal/vertical layout options via dagre
- Click node to view details, double-click to edit
- Respects all 32 themes via CSS variables
- Reduced motion support for animations

New dependencies: @xyflow/react, dagre

apps/ui/package.json

@@ -63,9 +63,11 @@
     "@xterm/addon-web-links": "^0.11.0",
     "@xterm/addon-webgl": "^0.18.0",
     "@xterm/xterm": "^5.5.0",
+    "@xyflow/react": "^12.10.0",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "cmdk": "^1.1.1",
+    "dagre": "^0.8.5",
     "dotenv": "^17.2.3",
     "geist": "^1.5.1",
     "lucide-react": "^0.562.0",
@@ -94,6 +96,7 @@
     "@playwright/test": "^1.57.0",
     "@tailwindcss/vite": "^4.1.18",
     "@tanstack/router-plugin": "^1.141.7",
+    "@types/dagre": "^0.7.53",
     "@types/node": "^22",
     "@types/react": "^19.2.7",
     "@types/react-dom": "^19.2.3",