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/preact/compat/src/forwardRef.js

@@ -0,0 +1,44 @@
+import { options } from 'preact';
+import { assign } from './util';
+
+let oldDiffHook = options._diff;
+options._diff = vnode => {
+	if (vnode.type && vnode.type._forwarded && vnode.ref) {
+		vnode.props.ref = vnode.ref;
+		vnode.ref = null;
+	}
+	if (oldDiffHook) oldDiffHook(vnode);
+};
+
+export const REACT_FORWARD_SYMBOL =
+	(typeof Symbol != 'undefined' &&
+		Symbol.for &&
+		Symbol.for('react.forward_ref')) ||
+	0xf47;
+
+/**
+ * Pass ref down to a child. This is mainly used in libraries with HOCs that
+ * wrap components. Using `forwardRef` there is an easy way to get a reference
+ * of the wrapped component instead of one of the wrapper itself.
+ * @param {import('./index').ForwardFn} fn
+ * @returns {import('./internal').FunctionComponent}
+ */
+export function forwardRef(fn) {
+	function Forwarded(props) {
+		let clone = assign({}, props);
+		delete clone.ref;
+		return fn(clone, props.ref || null);
+	}
+
+	// mobx-react checks for this being present
+	Forwarded.$$typeof = REACT_FORWARD_SYMBOL;
+	// mobx-react heavily relies on implementation details.
+	// It expects an object here with a `render` property,
+	// and prototype.render will fail. Without this
+	// mobx-react throws.
+	Forwarded.render = fn;
+
+	Forwarded.prototype.isReactComponent = Forwarded._forwarded = true;
+	Forwarded.displayName = 'ForwardRef(' + (fn.displayName || fn.name) + ')';
+	return Forwarded;
+}