fix(studio): a focused video or audio player keeps its arrow and play keys

[miguel-heygen]

What changes

With a video or audio player focused (the asset preview's native controls), the keys Studio's shortcuts used to take from it now go to that player only: the arrow keys and Space, plus the playback letters (J, K, L and the rest) and the canvas, caption and snap keys. Before, the playback shortcuts claimed the arrows first: the timeline playhead stepped, the key never reached the player, and the playhead move closed the asset preview.

Why it was broken

Every Studio key handler asks "does the focused element own this key?" before acting. The shared answer (isTypingTarget) covers text fields, editors, switches and comboboxes, but not a native media player, which seeks and plays with these keys itself. The playback shortcuts and the canvas nudge both relied on it.

What this does

• ownsPlainKeys in utils/typingTarget.ts (added by feat(studio): fade handles ride the fade's end and the waveform shows the fade #4844 for sliders) now has one list of controls that own their plain keys: [role='slider'], video[controls] and audio[controls], on top of anything isTypingTarget claims. There is no second predicate.
• The playback shortcuts (shouldIgnorePlaybackShortcutTarget, which the timeline player's key handler also goes through), the canvas arrow nudge, the caption-word arrow nudge and the preview's S/G snap keys use it, and so does the app's plain-key dispatcher (feat(studio): fade handles ride the fade's end and the waveform shows the fade #4844), so Delete on a focused player no longer deletes the selected clip.
• Three handlers kept their own copy of the text-input check: the timeline's N (snapping), K (add keyframe) and the automation selection keys (Delete, Cmd+C, Cmd+V). They now call isTypingTarget, so a focused picker such as the font combobox keeps its keys there too.
• The slideshow panel's in-panel Cmd+Z checked only INPUT and TEXTAREA, so Cmd+Z in a contenteditable or a select undid the panel instead of the text. It now calls isTypingTarget (a Cmd shortcut belongs to a text field, not to a slider).
• The playback shortcuts' own selector list dropped its slider, combobox, switch and textbox rows: ownsPlainKeys runs first and already claims them.
• shouldHandleTimelineDeleteKey was dead code (re-exported from Timeline.tsx, called only by its own test) with its own copy of the typing check. Deleted with its tests.
• Deliberate: N, K and the automation keys now also ignore a focused switch or combobox, the same as the app hotkeys already do. After flipping a switch (focus stays on it), K does nothing until focus moves.
• The snap keys keep their existing exclusion of a focused preview iframe: a key aimed at the composition is not a Studio shortcut.

Handlers checked

Handler	Keys	Predicate
Playback shortcuts (usePlaybackKeyboard)	arrows, Space, J/K/L and the other playback letters	ownsPlainKeys (changed)
Timeline player keys (useTimelinePlayer)	same, via shouldIgnorePlaybackShortcutTarget	ownsPlainKeys (inherited)
Canvas nudge (useDomEditNudge)	arrows	ownsPlainKeys (changed)
Caption-word nudge (captions/keyboard.ts)	arrows	ownsPlainKeys (changed)
Snap and grid (SnapToolbar)	S, G	ownsPlainKeys (was its own tag check)
Snapping toggle (TimelineToolbar)	N	isTypingTarget (was its own tag check)
Add keyframe (useKeyframeKeyboard)	K	isTypingTarget (was its own copy)
Automation selection (useAutomationSelectionKeyboard)	Delete, Backspace, Escape, Cmd+C, Cmd+V	isTypingTarget (was its own copy)
Slideshow panel undo (SlideshowPanel)	Cmd+Z inside the panel	isTypingTarget (was an INPUT/TEXTAREA tag check)
App plain keys (dispatchPlainKey)	letters, Delete	ownsPlainKeys (from #4844; now also covers players)
App chords (dispatchModifierKey, useAppHotkeys)	Cmd shortcuts	isTypingTarget, unchanged: a slider or player does not own Cmd+Z, copy or group
Undo and redo (shouldIgnoreHistoryShortcut)	Cmd+Z, Cmd+Shift+Z	isTypingTarget, unchanged, same reason
Timeline row navigation (timelineKeyboardNavigation)	arrows inside the timeline rows	not affected: it only runs with focus inside the timeline

Tests that fail without the fix

• usePlaybackKeyboard.test.ts: "leaves the timeline alone while a
• useDomEditNudge.test.tsx: "does not nudge the selection while a
• captions/keyboard.test.ts: "leaves the arrows to a focused
• SnapToolbar.test.tsx: "leaves S and G alone while a combobox / select / switch / video player has focus" (four rows).
• typingTarget.test.ts: "is true for a native player with controls and for anything typing claims".
• useAppHotkeys.test.ts: "leaves Delete to a focused
• TimelineToolbar.test.tsx: "N toggles snapping, but not while a picker that owns typing has focus".
• useKeyframeKeyboard.test.tsx: "leaves K to a focused picker that owns typing, like a font combobox".
• useAutomationSelectionKeyboard.test.tsx: "is inert while a picker that owns typing has focus".
• SlideshowPanel.test.ts: "leaves Cmd+Z to a text field, contenteditable and select included".

A video without controls still lets the playback keys step the timeline (tested).

Before

A small fixture project with one 20 s video asset not yet on the timeline. The asset preview is open with its video paused at 0:02 and focused:

ArrowRight: the timeline playhead steps from frame 0 to frame 1, the video never sees the key, and the preview closes because the playhead moved.

After

The same steps: the playhead stays on frame 0, the video seeks from 2.00 s to 2.20 s, and the preview stays open.

[github-actions]

Edit accuracy: 846 passing here, 846 on the base branch

The gate passes.
Smoothness is reported in the artifact, not gated. A case fails only if it fails 2 of 3 runs.

Quarantined, measured but not gated (2)

• sequndo-none-px-r0-root-z100 (fixed by part C (fix(studio): undo right after an edit undoes that edit, even before its save lands #4807 stack)): pass, passes
• seqrepeat-none-px-r0-nested-z100 (fixed by part C (fix(studio): undo right after an edit undoes that edit, even before its save lands #4807 stack)): pass, passes