Take updates from trevato/cs #375

This merges trevato/cs main (82a8a65, staged at refs/following/main) in two commits. The merge commit (7bd3e52) keeps this repository's tree for every conflicted file, so its tree is byte-for-byte this branch's. The one new upstream change that fits here, #228 (fall damage), is ported onto the engine layout in its own commit so it can be reviewed alone.

The git merge base is still #179, because earlier syncs were squashed. #367 and #371 already decided #188–#226, so only #223, #227 and #228 are new.

Per file:

• This side won in src/client/{bots,hud,main,motion,report,weapons,world}.ts and their tests, src/db.ts and db.test.ts, src/pages/game.ts and game.test.ts, and src/rl/arena.test.ts. Upstream's text there is the pre-extraction version of work this repo already has, the same decision as #367 and #371.

- Upstream's report.ts change names a fall in the round's damage report. Here report.ts is the result poster, and there is no damage report to name it in.

• This side won in src/client/{bodies,earshot,input,physics,plan,renderer,settings}.ts, their tests and src/readme.test.ts: they stay deleted. Their jobs live in src/engine/ (controls, renderer, physics) and in src/plan/.
• Upstream src/client/zoom.ts and zoom.test.ts: dropped again. src/client/look.ts already does scoped sensitivity.
• #223 (no-JS notice in the menu): not ported. This repo already covers it: Play and the room buttons are server-rendered disabled, and a <noscript> line from the game's registry entry says why. Upstream's inline <style> inside <noscript> would also break this repo's hash-pinned style CSP.
• #227 (a bot detours to a dropped rifle): not ported. Nothing in this repo puts a gun on the floor: there are no pickups, and nothing drops a weapon. The detour would have no target, so porting it would add dead code, the same reason #367 left out #222's worthTheDetour.
• #228 (fall damage): ported.

- Engine (src/engine/physics.ts): move now returns the speed a body met the floor at on the tick a fall ends, and 0 on every other tick. - This is a measurement, not a game rule, so the engine can report it. The list of exported names is unchanged, the three callers that ignore the result are untouched, and no Body literal changes. - Four new tests in physics.test.ts, run on both profiles: a drop reports v²=2gh once, a jump lands at the speed it left with, walking never reports a landing, and a bounce is not a landing. - GUIDE.md now says what move returns. - Game (src/client/world.ts): land charges fallDamage from movement.ts, rounded to whole points, and armour doesn't reduce it. - Only the person gets a hurt effect, recorded at their own feet. - A death to it is a feed line with the victim on both sides and cause "fall", and no kill or money goes to anyone. - FeedEntry.weapon becomes Cause = WeaponId | "fall", shown through causeName. A cause string off a room's wire that this build doesn't know is shown as itself instead of crashing the frame. - HUD (src/client/hud.ts): a hurt from straight below draws the pain flash but no arc, and the feed reads Pike Fall Pike. - Tests: new ones in world.test.ts and hud.test.ts. - One existing test changed only because the feed type got wider: in grenade.test.ts, WEAPONS[entry.weapon].name became causeName(entry.weapon). The test wasn't wrong; the old line no longer type-checks. - What players will notice: nothing on the current maps. - Every level has floors at 0, 2, 64 and 128 units, plus 384-unit walls. I checked de_forge and 200 generated seeds. - The highest floor anyone can stand on is a 128-unit crate, which lands at about 452 u/s, under the 580 u/s where damage starts. - No replay pin moved. The README says this next to the tagging paragraph.

bun run test (typecheck, then bun test) passes 1521 of 1521. The booted app answers / with a 200 in 15 ms. In the preview, the game should play exactly as before. A fall only costs health from about 210 units up, and no floor on these maps is that high.

Closes #372

🤖 Generated with Claude Code

Closes #372