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/prompts/dist/dateparts/seconds.js

@@ -0,0 +1,29 @@
+'use strict';
+
+const DatePart = require('./datepart');
+
+class Seconds extends DatePart {
+  constructor(opts = {}) {
+    super(opts);
+  }
+
+  up() {
+    this.date.setSeconds(this.date.getSeconds() + 1);
+  }
+
+  down() {
+    this.date.setSeconds(this.date.getSeconds() - 1);
+  }
+
+  setTo(val) {
+    this.date.setSeconds(parseInt(val.substr(-2)));
+  }
+
+  toString() {
+    let s = this.date.getSeconds();
+    return this.token.length > 1 ? String(s).padStart(2, '0') : s;
+  }
+
+}
+
+module.exports = Seconds;