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/css.escape/README.md

@@ -0,0 +1,39 @@
+# `CSS.escape` polyfill [![Build status](https://travis-ci.org/mathiasbynens/CSS.escape.svg?branch=master)](https://travis-ci.org/mathiasbynens/CSS.escape) [![Code coverage status](http://img.shields.io/coveralls/mathiasbynens/CSS.escape/master.svg)](https://coveralls.io/r/mathiasbynens/CSS.escape)
+
+A robust polyfill for [the `CSS.escape` utility method as defined in CSSOM](https://drafts.csswg.org/cssom/#the-css.escape%28%29-method).
+
+For a more powerful alternative, consider using [cssesc](https://mths.be/cssesc), which automatically takes care of excessive whitespace, and has many options to customize the output.
+
+## Installation
+
+In a browser:
+
+```html
+<script src="css.escape.js"></script>
+```
+
+Via [npm](https://www.npmjs.com/):
+
+```bash
+npm install css.escape
+```
+
+Then, in [Node.js](https://nodejs.org/):
+
+```js
+require('css.escape');
+
+// On Windows and on Mac systems with default settings, case doesn’t matter,
+// which allows you to do this instead:
+require('CSS.escape');
+```
+
+## Author
+
+| [![twitter/mathias](https://gravatar.com/avatar/24e08a9ea84deb17ae121074d0f17125?s=70)](https://twitter.com/mathias "Follow @mathias on Twitter") |
+|---|
+| [Mathias Bynens](https://mathiasbynens.be/) |
+
+## License
+
+This polyfill is available under the [MIT](https://mths.be/mit) license.