Add genlocke creation wizard with backend API and 4-step frontend

Implements the genlocke creation feature end-to-end: Genlocke and
GenlockeLeg models with migration, POST /genlockes endpoint that
creates the genlocke with all legs and auto-starts the first run,
and a 4-step wizard UI (Name, Select Games with preset templates,
Rules, Confirm) at /genlockes/new.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/Layout.tsx

@@ -28,6 +28,12 @@ export function Layout() {
               >
                 My Runs
               </Link>
+              <Link
+                to="/genlockes/new"
+                className="px-3 py-2 rounded-md text-sm font-medium hover:bg-gray-100 dark:hover:bg-gray-700"
+              >
+                Genlockes
+              </Link>
               <Link
                 to="/stats"
                 className="px-3 py-2 rounded-md text-sm font-medium hover:bg-gray-100 dark:hover:bg-gray-700"
@@ -93,6 +99,13 @@ export function Layout() {
               >
                 My Runs
               </Link>
+              <Link
+                to="/genlockes/new"
+                onClick={() => setMenuOpen(false)}
+                className="block px-3 py-2 rounded-md text-base font-medium hover:bg-gray-100 dark:hover:bg-gray-700"
+              >
+                Genlockes
+              </Link>
               <Link
                 to="/stats"
                 onClick={() => setMenuOpen(false)}