feat(stdlib): new modules + eslint/tsconfig migration

- Add array/async/etc. modules and type tests; migrate to eslint flat config
  and composite tsconfig (vitest typecheck enabled).
- Fix PubSub.emit to snapshot listeners before iterating (stable EventEmitter
  semantics; avoids invoking listeners added during the same emit).

core/stdlib/src/collections/get/index.ts

@@ -27,8 +27,40 @@ export type ExtractFromCollection<O, K>
           : never
       : never;
 
-type Get<O, K> = ExtractFromCollection<O, Path<K>>;
+export type Get<O, K> = ExtractFromCollection<O, Path<K>>;
 
-export function get<O extends Collection, K extends string>(obj: O, path: K) {
-  return path.split('.').reduce((acc, key) => (acc as any)?.[key], obj) as Get<O, K> | undefined;
+/**
+ * @name get
+ * @category Collections
+ * @description Safely read a deeply nested value from a collection by a dot-separated path
+ *
+ * @param {Collection} obj - The source object or array
+ * @param {string} path - Dot-separated path, e.g. `'user.addresses.0.street'`
+ * @returns {Get<O, K> | undefined} The resolved value, or `undefined` if any segment is missing
+ *
+ * @example
+ * get({ user: { name: 'John' } }, 'user.name'); // 'John'
+ * get({ items: [{ id: 1 }] }, 'items.0.id'); // 1
+ * get({ a: 1 }, 'a.b.c'); // undefined
+ *
+ * @since 0.0.4
+ */
+export function get<O extends Collection, K extends string>(obj: O, path: K): Get<O, K> | undefined {
+  let value: any = obj;
+  let start = 0;
+
+  // Walk the path without allocating an intermediate array of segments.
+  for (let i = 0, len = path.length; i <= len; i++) {
+    // Split on '.' (char code 46) or the end of the string.
+    if (i !== len && path.charCodeAt(i) !== 46)
+      continue;
+
+    if (value === null || value === undefined)
+      return undefined;
+
+    value = value[path.slice(start, i)];
+    start = i + 1;
+  }
+
+  return value;
 }