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/__mocks__/next-dynamic.js

@@ -0,0 +1,27 @@
+// Synchronous mock for next/dynamic — resolves modules immediately in test env
+function dynamic(importFn, _options) {
+  let Component = null;
+
+  // Call the import function to get the promise, then extract synchronously
+  // In tests modules are already loaded, so we can do a trick:
+  // Return a wrapper that calls the import lazily on first render
+  const Wrapper = (props) => {
+    if (!Component) {
+      throw new Error(
+        'next/dynamic mock: module not yet resolved. Use jest.mock for the specific module instead.',
+      );
+    }
+    const React = require('react');
+    return React.createElement(Component, props);
+  };
+
+  // Resolve immediately (modules are synchronous in jest)
+  importFn().then((mod) => {
+    Component = mod.default || mod;
+  });
+
+  return Wrapper;
+}
+
+module.exports = dynamic;
+module.exports.default = dynamic;

frontend/__mocks__/next-navigation.js

@@ -0,0 +1,12 @@
+module.exports = {
+  useRouter: () => ({
+    push: jest.fn(),
+    replace: jest.fn(),
+    prefetch: jest.fn(),
+    back: jest.fn(),
+    pathname: '/',
+    query: {},
+  }),
+  usePathname: () => '/',
+  useSearchParams: () => new URLSearchParams(),
+};

frontend/__mocks__/react-force-graph-2d.js

@@ -0,0 +1,9 @@
+const React = require('react');
+
+// Stub for react-force-graph-2d — canvas APIs not available in jsdom
+function ForceGraph2D(props) {
+  return React.createElement('div', { 'data-testid': 'force-graph-2d' }, 'ForceGraph2D stub');
+}
+
+module.exports = ForceGraph2D;
+module.exports.default = ForceGraph2D;

frontend/__mocks__/styleMock.js

@@ -0,0 +1 @@
+module.exports = {};