add vim toggle to settings

+ added persistent global state store
+ refactored themes to use the new store

website/public/store.mjs

@@ -0,0 +1,36 @@
+export const storeKey = 'strudel-settings';
+
+export function get(prop) {
+  const state = JSON.parse(localStorage.getItem(storeKey));
+  if (!prop) {
+    return state;
+  }
+  return state[prop];
+}
+
+export function set(next) {
+  localStorage.setItem(storeKey, JSON.stringify(next));
+}
+
+export function updateState(func) {
+  const prev = get();
+  const next = func(prev);
+  set(next);
+  document.dispatchEvent(
+    new CustomEvent(storeKey, {
+      detail: { next, prev },
+    }),
+  );
+}
+
+export function watch(func, prop) {
+  document.addEventListener(storeKey, (e) => {
+    const { prev, next } = e.detail;
+    const hasPropChanged = (p) => next[p] !== prev[p];
+    if (!prop) {
+      func(next);
+    } else if (hasPropChanged(prop)) {
+      func(next[prop]);
+    }
+  });
+}