feat: add shared q() qs() DOM helpers

static/q.ts

@@ -0,0 +1,8 @@
+export const q = <T extends Element>(container: HTMLElement, selector: string): T | null =>
+  container.querySelector(selector) as T | null
+
+export const qs = <T extends Element>(selector: string): T | null =>
+  document.querySelector(selector) as T | null
+
+export const dataset = (el: HTMLElement, key: string): string =>
+  el.dataset[key] ?? ''