feat(ui): 3-tab UI per spec — admin dashboard + date filter, personal dashboard, training w/ difficulty, settings profile

Tab 1 Admin overview (/): aggregate stats + DATE FILTER (?from&to), hardest personas,
admin quick actions (Users / + Add product).
Tab 2 My dashboard (/my/board): per-user win/lose/session summary (works for admin too).
Tab 3 Training (/training): product list w/ status + persona count; admins see all groups
(draft->analyze/edit), trainees see ready->personas; persona list shows DIFFICULTY (1-5
stars); admins get a Manage-personas button.
Settings (/settings): profile (name/email) via new PATCH /api/auth/profile + change
password + language.
Backend: analytics date filter; profile endpoint; /api/me/board + /api/chat/sessions
opened to any authed user.
Rebuilt frontend/dist.

backend/app/api/auth_routes.py

@@ -65,3 +65,20 @@ def setup():
         "user": _store().public_user(updated),
         "must_setup": False,
     })
+
+
+@auth_bp.patch("/profile")
+@require_auth
+def profile():
+    """Self-service profile update: name (and optional email). Any authenticated user."""
+    user = current_user()
+    data = request.get_json(silent=True) or {}
+    username = user.get("username") or user.get("id")
+    try:
+        if "name" in data:
+            _store().set_name(username, data.get("name"))
+        if "email" in data:
+            _store().set_email(username, data.get("email"))
+    except AuthError as exc:
+        raise ApiError(str(exc), 400)
+    return jsonify({"user": _store().public_user(_store().get_user(username))})