fix(engine): harden DOM mask visibility restore

[miguel-heygen]

Summary

• Preserve and restore previous inline visibility for every element temporarily hidden by the HDR DOM layer mask, including extraHideIds and __render_frame_* replacement images.
• This is defensive hardening around the same class of DOM-mask visibility state issues, but it is not the root fix for HDR layered composite path renders timed DOM overlays (subtitles) stuck on their last state #1952.

#1952 Repro Follow-up

I reproduced #1952 with the exact true-HDR minimal repro against v0.7.31: sampled subtitle-bar pixels at t=1.5/4.5/7.5 are all blue (0000ff), matching the reported stuck SUB 2 behavior.

The same repro passes on current main and on this branch: samples are red/green/blue (ff0000, 00ff00, 0000ff). It also passes on this branch's parent 78cca797f / v0.7.33, so this PR is not the root fix for #1952.

The actual root fix for #1952 is already on main: bb066077b / PR #1935 (fix(producer): avoid reviving hidden DOM in HDR layers), included in v0.7.33.

Validation

• bunx oxfmt --check packages/engine/src/services/screenshotService.ts packages/engine/src/services/screenshotService.test.ts
• bunx oxlint packages/engine/src/services/screenshotService.ts packages/engine/src/services/screenshotService.test.ts
• bun run --filter @hyperframes/engine typecheck
• bun run --filter @hyperframes/engine build
• bun run --filter @hyperframes/engine test src/services/screenshotService.test.ts
• bunx vitest run packages/producer/src/services/render/stages/captureHdrFrameShared.dom-mask.test.ts packages/producer/src/services/render/stages/captureHdrFrameShared.test.ts