Duyphuc1901/lc79 — reverse-engineered prompt

Build me a simple JavaScript project for LC79, the word search problem. I want to open a small local web page, enter a grid of letters and a target word, then click a button to see whether the word can be found by moving up, down, left, or right through neighboring cells, without using the same cell twice. Keep it easy to understand for someone learning algorithms.

Please wire it up with a basic Node server, put the solving logic in its own file, and make the page show the result clearly, plus a short explanation of the path if it finds one. Add a couple of sample grids so I can test it right away. Also handle simple mistakes like empty input, uneven rows, or lowercase letters. Keep the code clean and commented enough that I can study it later. If you need to check the exact LC79 rules, look them up online.