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/next/dist/shared/lib/page-path/remove-page-path-tail.d.ts

@@ -0,0 +1,15 @@
+/**
+ * Removes the file extension for a page and the trailing `index` if it exists
+ * making sure to not return an empty string. The page head is not touched
+ * and returned as it is passed. Examples:
+ *   - `/foo/bar/baz/index.js` -> `/foo/bar/baz`
+ *   - `/foo/bar/baz.js` -> `/foo/bar/baz`
+ *
+ * @param pagePath A page to a page file (absolute or relative)
+ * @param options.extensions Extensions allowed for the page.
+ * @param options.keepIndex When true the trailing `index` is _not_ removed.
+ */
+export declare function removePagePathTail(pagePath: string, options: {
+    extensions: ReadonlyArray<string>;
+    keepIndex?: boolean;
+}): string;