fix(studio): honor selected render resolution - #2876

What

Fix Studio exports so selecting 4K submits the canonical orientation-specific resolution preset instead of silently falling back to the composition's native dimensions. Also make Studio thumbnail/browser startup honor the same browser overrides as the CLI and contain transient launch failures.

Why

Studio displayed 4K · 3840×2160, but sent the UI-only value 4k to the render API. The API accepts canonical presets such as landscape-4k, so it discarded the invalid alias and rendered a 1920×1080 composition at 1080p. Separately, a failed shared-browser launch could escape thumbnail error handling and terminate the Studio dev server.

How

• Resolve auto / 1080p / 4k to the canonical aspect-aware preset before telemetry and render submission.
• Source CanvasResolution and CANVAS_DIMENSIONS directly from the browser-safe parser package shared with the CLI/core path.
• Respect HYPERFRAMES_BROWSER_PATH and the legacy PRODUCER_HEADLESS_SHELL_PATH alias before system Chrome paths.
• Keep browser launch inside the thumbnail error boundary, reset failed launch state for retry, and observe in-flight cleanup rejections.

Test plan

• Unit tests added/updated
• Manual testing performed
• Documentation updated (not applicable)

Verification:

• Full Studio suite: 3,117 passed (18 todo)
• Studio typecheck, build, oxfmt, oxlint, commit hooks: pass
• Browser E2E through hyperframes preview: select 4K + 60 fps, render, download through the Studio route
• Downloaded MP4 (ffprobe): H.264, 3840×2160, 60/1 fps, 240 frames, 4.000s
• Failure-path smoke: two invalid browser launches return bounded thumbnail 500s; Studio health endpoint remains 200 and the second launch retries