Add Pancake Griddle: the playable page and its place in the catalogue, on the rules in `pancake-griddle/griddle.js` #301

A new game in the house style, mounted like the other forged games and built on the tested rules in pancake-griddle/griddle.js.

Done looks like:

• [ ] pancake-griddle/index.html draws a fair-day stall with a griddle of rings, pancakes browning on them, and the waiting customers with their patience shown. Tap a ring to pour, flip or serve it, whichever its state allows. The number keys pick a ring, and Enter acts on it. The page drives the game only through pancake-griddle/griddle.js and adds no game rule of its own. The HUD shows what the rules state reports, and each action and each lost life is announced through an aria-live region.
• [ ] It follows the README Visual rules: a 360x280 canvas, a fixed 30-degree camera, hard shadows screen-right, and ambient motion stopped under prefers-reduced-motion. Raw, golden and burnt differ by texture and a steam or smoke mark as well as colour, and the HUD shows lives as pancakes, not only as a number. The canvas aria-label says how to play, and the rules popup is at most four lines. There is a #mute button, and no .mp3 is committed.
• [ ] GAMES in shell.js lists it as { id: 'pancake-griddle', title: 'Pancake Griddle', blurb: 'Pour, flip and serve golden pancakes before the griddle burns them', kind: 'Timing', input: 'Tap', accent: '#d9a441', music: false, forged: true }. It has the matching <li> in the root index.html, a building in the town from town.js like every other game, and a place in the README Games table and the list of games without music. bun scripts/og.mjs has been run.
• [ ] rounds.mjs has a scripted round for pancake-griddle that reaches the end line. serve.test.mjs asserts that /pancake-griddle/ and /pancake-griddle/griddle.js answer 200. playtest.test.mjs passes for the folder, and bun test passes. Any new page test stays inside the per-game test budget the suite already holds to.

Files: pancake-griddle/index.html, shell.js, index.html, town.js if buildings are listed there, README.md, serve.test.mjs, rounds.mjs, og/. Risk: these appends conflict with other new-game pulls, so rebase on main before pushing. Fits: a builder.

Waits for the rules issue to land on main.