Add side panels, task selection, graph animation, and project docs

- Foldable left panel (user profile) and right panel (task details)
- Clicking a task in the list or graph node selects it and shows details
- Both views (task list + graph) always mounted via absolute inset-0 for
  correct canvas dimensions; tabs toggle visibility with opacity
- Graph node selection animation: other nodes repel outward (charge -600),
  then selected node smoothly slides to center (500ms cubic ease-out),
  then charge restores to -120 and graph stabilizes
- Graph re-fits on tab switch and panel resize via ResizeObserver
- Fix UUID string IDs throughout (backend returns UUIDs, not integers)
- Add TaskDetailPanel, UserPanel components
- Add CLAUDE.md project documentation

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

frontend/node_modules/queue-microtask/index.js

@@ -0,0 +1,9 @@
+/*! queue-microtask. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
+let promise
+
+module.exports = typeof queueMicrotask === 'function'
+  ? queueMicrotask.bind(typeof window !== 'undefined' ? window : global)
+  // reuse resolved promise, and allocate it lazily
+  : cb => (promise || (promise = Promise.resolve()))
+    .then(cb)
+    .catch(err => setTimeout(() => { throw err }, 0))