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/internmap/src/index.js

@@ -0,0 +1,61 @@
+export class InternMap extends Map {
+  constructor(entries, key = keyof) {
+    super();
+    Object.defineProperties(this, {_intern: {value: new Map()}, _key: {value: key}});
+    if (entries != null) for (const [key, value] of entries) this.set(key, value);
+  }
+  get(key) {
+    return super.get(intern_get(this, key));
+  }
+  has(key) {
+    return super.has(intern_get(this, key));
+  }
+  set(key, value) {
+    return super.set(intern_set(this, key), value);
+  }
+  delete(key) {
+    return super.delete(intern_delete(this, key));
+  }
+}
+
+export class InternSet extends Set {
+  constructor(values, key = keyof) {
+    super();
+    Object.defineProperties(this, {_intern: {value: new Map()}, _key: {value: key}});
+    if (values != null) for (const value of values) this.add(value);
+  }
+  has(value) {
+    return super.has(intern_get(this, value));
+  }
+  add(value) {
+    return super.add(intern_set(this, value));
+  }
+  delete(value) {
+    return super.delete(intern_delete(this, value));
+  }
+}
+
+function intern_get({_intern, _key}, value) {
+  const key = _key(value);
+  return _intern.has(key) ? _intern.get(key) : value;
+}
+
+function intern_set({_intern, _key}, value) {
+  const key = _key(value);
+  if (_intern.has(key)) return _intern.get(key);
+  _intern.set(key, value);
+  return value;
+}
+
+function intern_delete({_intern, _key}, value) {
+  const key = _key(value);
+  if (_intern.has(key)) {
+    value = _intern.get(key);
+    _intern.delete(key);
+  }
+  return value;
+}
+
+function keyof(value) {
+  return value !== null && typeof value === "object" ? value.valueOf() : value;
+}