refactor: add TypeScript type annotations to fix implicit 'any' errors

Fixed 12 type errors by adding proper type annotations:

Quick Wins Completed:
- do_on_key.js: Added JSDoc types for KeyboardEvent and function parameters
- randomize.js: Added JSDoc types with generic template for array shuffling
- cookie.js: Added JSDoc types for Request API
- stripHtmlTags.ts: Added TypeScript types for string parameter

Progress: 12/1239 errors fixed (Quick Wins - Category 1 partial)

Created TODO_cleanup.md to track remaining 1227 type errors systematically.

src/lib/components/do_on_key.js

@@ -1,3 +1,9 @@
+/**
+ * @param {KeyboardEvent} event
+ * @param {string} key
+ * @param {boolean} needsctrl
+ * @param {() => void} fn
+ */
 export function do_on_key(event, key, needsctrl, fn){
 	if(event.key == key){
 		if(needsctrl && !event.ctrlKey){

src/lib/js/randomize.js

@@ -1,4 +1,8 @@
 const MS_PER_DAY = 86400000
+
+/**
+ * @param {number} a
+ */
 function mulberry32(a) {
 	return function() {
 	  var t = a += 0x6D2B79F5;
@@ -8,6 +12,11 @@ function mulberry32(a) {
 	}
 }
 
+/**
+ * @template T
+ * @param {T[]} array
+ * @returns {T[]}
+ */
 export function rand_array(array){
 	let time = new Date()
 	const seed = Math.floor(time.getTime()/MS_PER_DAY)

src/lib/js/stripHtmlTags.ts

@@ -1,7 +1,7 @@
 // Function to strip HTML tags from a string
 import {load} from 'cheerio';
 
-export function stripHtmlTags(input) {
+export function stripHtmlTags(input: string): string {
   const $ = load(input.replace(/­/g, ''));
   return $.text();
 }