[Noisemaker111]

A Scrap Signal playtest couldn't fire its hold-to-fire guns: drive --key mouse0:1200 sent mouse0 as a keyboard code, which nothing reads. Only --click-at fired, one round per click.

• templates/gameSurfaceFocus.ts: mouseButtonForCode maps the shell's pointer binding codes (mouse0/mouse1/mouse2) to the CDP button and buttons mask; gameSurfaceCenter returns the play canvas centre. Both are self-contained, so they embed into drive.mjs like the existing helpers.
• holdKey in the drive template: a mouse code moves to the canvas centre, presses, waits with the same duration-plus-one-frame rule as key holds, then releases. Keyboard codes are unchanged. Usage text and the scaffold's agent notes mention it; changes/drive-mouse-hold.md.

Verification

• bun test packages/jgengine/src/templates packages/jgengine/src/driveNative.test.ts — 61 pass, 0 fail (5 new, including a serialization round-trip); check-types — pass; bun run gen — ok; ship:preflight — ok
• Live, Scrap Signal on this branch's CLI build: --click "GUNK" --wait 30000 --key mouse0:8000 took the pistol from 12 to 11 rounds. Headless runs at about 0.2 fps, so one shot fits in the hold.

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Generated by Claude Code

[Noisemaker111]

test failed on CreatorApp.test.ts › "unsaved and pending failed saves survive native play, pause, resume and return". That editor browser test also flaked on #1990, before any of today's changes, and this PR only changes the drive template's mouse holds. I merged the latest beta and pushed, which re-runs CI. I can't re-run the jobs directly (403).

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Generated by Claude Code