Add Tide Crossing: the playable page and its place in the catalogue, on the rules in `tide-crossing/causeway.js` #352

Tide Crossing is added as a playable page on the rules in tide-crossing/causeway.js, which I left untouched. It's on the branch and rebased on main, which had nothing new. I didn't run the full bun test; the forge's check runs it on this push. Before pushing, serve.test.mjs, shell.test.mjs, town.test.mjs, the new tide-crossing/page.test.mjs and the Tide Crossing cases in playtest.test.mjs all passed. The repo has no scripts/gate.ts, no scripts/design-lint.ts and no tsconfig, so bun x tsc --noEmit only prints its help text and I ran none of them.

What changed

• Page: tide-crossing/index.html draws the causeway as stone slabs under the fixed 30-degree camera, with hard shadows screen-right and lapping foam that stops under prefers-reduced-motion.

- Scene: the sand start stone, the island stone with a flag, the walker, and blue water with wave lines over every stone covered at the current tick. A tide gauge at the left shows the water level and next tick's level. - Ripple edge: a stone that goes under next tick gets a dashed ripple ring as well as the HUD naming it. - Input: arrows or WASD call move, Space calls wait. On touch, tapping a neighbouring stone steps there and tapping the walker's stone waits. After a win a tap goes to the next level, and after a loss it restarts. - Keys and HUD: R restarts and N goes to the next level after a win. The HUD shows the level name, tick, "Moves N of par P" and the stones going under next tick. - Announcements: each move, each refusal reason and the state's line go through an aria-live region. There is a #mute button with synthesized sound, no .mp3, and the rules popup is four lines.

• Catalogue:

- shell.js has the GAMES entry (id tide-crossing, Puzzle, Keys, music: false, forged: true) and index.html has the matching <li>. - The town building comes from town.js automatically, since it lays out buildings from GAMES. - The README has the Games row, the no-music list and the reduced-motion note. - og/tide-crossing.png and og/home.png are regenerated with bun scripts/og.mjs.

• Tests:

- rounds.mjs has a scripted round that plays the first level's stated solution to "Crossed in 3 ticks against par 3: on par". - serve.test.mjs checks that /tide-crossing/ and /tide-crossing/causeway.js answer 200. - tide-crossing/page.test.mjs covers keys, refusal messages, the next-tick list, losing, restart, touch taps and reduced motion.

What I chose not to do

• No save of the current level; the issue didn't ask for one.
• "Under next tick" is read from the rules' own tideAt and the stated tide[t] >= h rule, because causeway.js has no function that lists those stones. A small helper there would let the page drop that read.

The tide gauge and the drawn stone height (0.5 + 0.12 × height) are my own visual choices, so I'd look at the preview for those.

Closes #349

Tide Crossing is added as a playable page on the rules in tide-crossing/causeway.js, which I left untouched. It's on the branch and rebased on main, which had nothing new. I didn't run the full bun test; the forge's check runs it on this push. Before pushing, serve.test.mjs, shell.test.mjs, town.test.mjs, the new tide-crossing/page.test.mjs and the Tide Crossing cases in playtest.test.mjs all passed. The repo has no scripts/gate.ts, no scripts/design-lint.ts and no tsconfig, so bun x tsc --noEmit only prints its help text and I ran none of them.

What changed

• Page: tide-crossing/index.html draws the causeway as stone slabs under the fixed 30-degree camera, with hard shadows screen-right and lapping foam that stops under prefers-reduced-motion.

- Scene: the sand start stone, the island stone with a flag, the walker, and blue water with wave lines over every stone covered at the current tick. A tide gauge at the left shows the water level and next tick's level. - Ripple edge: a stone that goes under next tick gets a dashed ripple ring as well as the HUD naming it. - Input: arrows or WASD call move, Space calls wait. On touch, tapping a neighbouring stone steps there and tapping the walker's stone waits. After a win a tap goes to the next level, and after a loss it restarts. - Keys and HUD: R restarts and N goes to the next level after a win. The HUD shows the level name, tick, "Moves N of par P" and the stones going under next tick. - Announcements: each move, each refusal reason and the state's line go through an aria-live region. There is a #mute button with synthesized sound, no .mp3, and the rules popup is four lines.

• Catalogue:

- shell.js has the GAMES entry (id tide-crossing, Puzzle, Keys, music: false, forged: true) and index.html has the matching <li>. - The town building comes from town.js automatically, since it lays out buildings from GAMES. - The README has the Games row, the no-music list and the reduced-motion note. - og/tide-crossing.png and og/home.png are regenerated with bun scripts/og.mjs.

• Tests:

- rounds.mjs has a scripted round that plays the first level's stated solution to "Crossed in 3 ticks against par 3: on par". - serve.test.mjs checks that /tide-crossing/ and /tide-crossing/causeway.js answer 200. - tide-crossing/page.test.mjs covers keys, refusal messages, the next-tick list, losing, restart, touch taps and reduced motion.

What I chose not to do

• No save of the current level; the issue didn't ask for one.
• "Under next tick" is read from the rules' own tideAt and the stated tide[t] >= h rule, because causeway.js has no function that lists those stones. A small helper there would let the page drop that read.

The tide gauge and the drawn stone height (0.5 + 0.12 × height) are my own visual choices, so I'd look at the preview for those.

I merged main into the branch and pushed it. The branch now has both Tide Crossing and Pumpkin Patch, which arrived from main.

• Tests: I ran serve.test.mjs and the tide-crossing tests: 111 pass, 0 fail. I did not run the full suite; the forge's check does that on the push.
• Type check: bun x tsc --noEmit printed only its usage help, so I take it the repo has no tsconfig, and that check did not run.
• README.md: I kept both catalogue rows. The "add a game" music list and the ambient-motion list now name Tide Crossing alongside Pumpkin Patch.
• shell.js: both GAMES entries are kept.
• serve.test.mjs: both games' "served without a track" tests are kept.
• og/home.png: I regenerated it with bun scripts/og.mjs, so the collage includes both games and the serve test's byte-for-byte check still holds.

Left #349 open: 1 unticked item remain (rounds.mjs has a scripted round for tide-crossing that reaches the end line (the first level's solution is in the rules). serve.test.mjs asserts that /tide-crossing/ and /tide-crossing/causeway.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.).