Fix lite UI story sheet keyboard spacing

[dannyhw]

Issue:

The lite UI story select sheet could not scroll all the way to the bottom while the keyboard was open. The scroll content did not account for the keyboard height, so the last stories could remain hidden behind the keyboard. The floating "Scroll to selected" button also stayed visible while typing and could overlap the searchable list.

What I did

• Track the keyboard height in the lite mobile menu drawer with platform-specific keyboard events.
• Provide the drawer keyboard inset to the story tree and search result lists.
• Add the keyboard inset to the virtualized list content padding so the bottom items remain reachable.
• Cap the keyboard-expanded sheet height lower so the sheet shows less content while the keyboard is open.
• Hide the "Scroll to selected" button while the keyboard is visible.

How to test

• Open the lite UI story select sheet on iOS and Android.
• Focus the search input so the keyboard opens.
• Confirm the list can scroll to the final story/search result without content being trapped behind the keyboard.
• Confirm the sheet does not expand too tall while the keyboard is open.
• Confirm the "Scroll to selected" button is hidden while the keyboard is open and returns when the keyboard is dismissed.

Checked locally with:

pnpm -F @storybook/react-native-ui-lite check:types

This does not need a new example in examples/expo-example and does not need a documentation update.

[changeset-bot]

🦋 Changeset detected

Latest commit: 0e30b6e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 9 packages

Name	Type
@storybook/react-native-ui-lite	Patch
@storybook/react-native	Patch
@storybook/react-native-ui	Patch
@storybook/react-native-ui-common	Patch
@storybook/react-native-theming	Patch
@storybook/addon-ondevice-actions	Patch
@storybook/addon-ondevice-backgrounds	Patch
@storybook/addon-ondevice-controls	Patch
@storybook/addon-ondevice-notes	Patch

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