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/domexception/webidl2js-wrapper.js

@@ -0,0 +1,15 @@
+"use strict";
+const DOMException = require("./lib/DOMException.js");
+
+// Special install function to make the DOMException inherit from Error.
+// https://heycam.github.io/webidl/#es-DOMException-specialness
+function installOverride(globalObject, globalNames) {
+  if (typeof globalObject.Error !== "function") {
+    throw new Error("Internal error: Error constructor is not present on the given global object.");
+  }
+
+  DOMException.install(globalObject, globalNames);
+  Object.setPrototypeOf(globalObject.DOMException.prototype, globalObject.Error.prototype);
+}
+
+module.exports = { ...DOMException, install: installOverride };