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/argparse/lib/action/append/constant.js

@@ -0,0 +1,47 @@
+/*:nodoc:*
+ * class ActionAppendConstant
+ *
+ * This stores a list, and appends the value specified by
+ * the const keyword argument to the list.
+ * (Note that the const keyword argument defaults to null.)
+ * The 'appendConst' action is typically useful when multiple
+ * arguments need to store constants to the same list.
+ *
+ * This class inherited from [[Action]]
+ **/
+
+'use strict';
+
+var util = require('util');
+
+var Action = require('../../action');
+
+/*:nodoc:*
+ * new ActionAppendConstant(options)
+ * - options (object): options hash see [[Action.new]]
+ *
+ **/
+var ActionAppendConstant = module.exports = function ActionAppendConstant(options) {
+  options = options || {};
+  options.nargs = 0;
+  if (typeof options.constant === 'undefined') {
+    throw new Error('constant option is required for appendAction');
+  }
+  Action.call(this, options);
+};
+util.inherits(ActionAppendConstant, Action);
+
+/*:nodoc:*
+ * ActionAppendConstant#call(parser, namespace, values, optionString) -> Void
+ * - parser (ArgumentParser): current parser
+ * - namespace (Namespace): namespace for output data
+ * - values (Array): parsed values
+ * - optionString (Array): input option string(not parsed)
+ *
+ * Call the action. Save result in namespace object
+ **/
+ActionAppendConstant.prototype.call = function (parser, namespace) {
+  var items = [].concat(namespace[this.dest] || []);
+  items.push(this.constant);
+  namespace.set(this.dest, items);
+};