Optimize composer command key bindings

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What Changed

Replaced the render-only ComposerCommandKeyPlugin component with a named useComposerCommandKeyBindings hook in ComposerPromptEditor.

Why

React Scan showed the command key plugin rerendering on every composer keystroke even though it only exists to register Lexical keyboard commands. The new hook registers those commands once against the Lexical editor and uses useEffectEvent to call the latest handler, removing that component from the typing render path while preserving Arrow/Enter/Tab behavior.

React Doctor was run for Performance/Maintainability. Its broad scan surfaced migration-scale existing findings; this PR addresses the manually confirmed composer hot spot and keeps scope focused.

UI Changes

No visual UI change.

React Scan before/after recordings captured with the render-count overlay enabled:

• Before: react_scan_composer_before_effect_fix.mp4 — ComposerCommandKeyPlugin increments during typing.
• After: react_scan_composer_after_command_hook.mp4 — ComposerCommandKeyPlugin count stays flat during typing.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

Validation:

• npx -y react-doctor@latest apps/web --diff main --category Performance --category Maintainability --no-telemetry --offline --verbose --blocking none
• NODE_OPTIONS="--experimental-strip-types" corepack pnpm exec vp check
• corepack pnpm exec vp run typecheck

  

Note

Replace ComposerCommandKeyPlugin with useComposerCommandKeyBindings hook in composer editor

Migrates command key binding logic from the ComposerCommandKeyPlugin React component into a useComposerCommandKeyBindings hook in ComposerPromptEditor.tsx. The hook registers handlers for arrow, enter, and tab commands at COMMAND_PRIORITY_HIGH and cleans them up on unmount, replacing the equivalent useEffect logic in the removed plugin component.

^{Macroscope summarized 7154e7c.}