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/d3-array/src/quantile.js

@@ -0,0 +1,47 @@
+import max from "./max.js";
+import maxIndex from "./maxIndex.js";
+import min from "./min.js";
+import minIndex from "./minIndex.js";
+import quickselect from "./quickselect.js";
+import number, {numbers} from "./number.js";
+import {ascendingDefined} from "./sort.js";
+import greatest from "./greatest.js";
+
+export default function quantile(values, p, valueof) {
+  values = Float64Array.from(numbers(values, valueof));
+  if (!(n = values.length) || isNaN(p = +p)) return;
+  if (p <= 0 || n < 2) return min(values);
+  if (p >= 1) return max(values);
+  var n,
+      i = (n - 1) * p,
+      i0 = Math.floor(i),
+      value0 = max(quickselect(values, i0).subarray(0, i0 + 1)),
+      value1 = min(values.subarray(i0 + 1));
+  return value0 + (value1 - value0) * (i - i0);
+}
+
+export function quantileSorted(values, p, valueof = number) {
+  if (!(n = values.length) || isNaN(p = +p)) return;
+  if (p <= 0 || n < 2) return +valueof(values[0], 0, values);
+  if (p >= 1) return +valueof(values[n - 1], n - 1, values);
+  var n,
+      i = (n - 1) * p,
+      i0 = Math.floor(i),
+      value0 = +valueof(values[i0], i0, values),
+      value1 = +valueof(values[i0 + 1], i0 + 1, values);
+  return value0 + (value1 - value0) * (i - i0);
+}
+
+export function quantileIndex(values, p, valueof = number) {
+  if (isNaN(p = +p)) return;
+  numbers = Float64Array.from(values, (_, i) => number(valueof(values[i], i, values)));
+  if (p <= 0) return minIndex(numbers);
+  if (p >= 1) return maxIndex(numbers);
+  var numbers,
+      index = Uint32Array.from(values, (_, i) => i),
+      j = numbers.length - 1,
+      i = Math.floor(j * p);
+  quickselect(index, i, 0, j, (i, j) => ascendingDefined(numbers[i], numbers[j]));
+  i = greatest(index.subarray(0, i + 1), (i) => numbers[i]);
+  return i >= 0 ? i : -1;
+}