fix(ui): support defaultValue in showFontPicker app environment

[SusTechStitch]

Fixes #2896.

Summary

This PR makes puter.ui.showFontPicker handle default font options consistently in the Puter app environment.

Changes:

• Normalize string shorthand, defaultFont, defaultValue, and legacy default before sending options to the app environment
• Support defaultValue, defaultFont, and default in UIWindowFontPicker
• Fix scrolling to the active default font by avoiding shadowing the global window
• Add defaultValue to FontPickerOptions

Testing

• git diff --check
• node --check src/puter-js/src/modules/UI.js
• node --check src/gui/src/UI/UIWindowFontPicker.js
• npm start

Manually tested in the Puter app environment:

await puter.ui.showFontPicker("Georgia");
await puter.ui.showFontPicker({ defaultFont: "Georgia" });
await puter.ui.showFontPicker({ defaultValue: "Georgia" });

All three calls open the font picker with Georgia preselected.

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[Copilot]

Pull request overview

This PR updates the puter.ui.showFontPicker SDK API and the app-environment font picker window to consistently honor a “default font” provided via string shorthand, defaultFont, defaultValue, or legacy default (Fixes #2896).

Changes:

• Normalize showFontPicker inputs in the SDK (string shorthand + multiple default-* option keys) before posting to the app environment.
• Update UIWindowFontPicker to read defaultValue/defaultFont/default and to scroll to the active default font without shadowing the global window.
• Extend TypeScript types with FontPickerOptions.defaultValue.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/puter-js/types/modules/ui.d.ts	Adds defaultValue to FontPickerOptions for typed support.
src/puter-js/src/modules/UI.js	Normalizes font picker options (including string shorthand) before app messaging and keeps web-component fallback consistent.
src/gui/src/UI/UIWindowFontPicker.js	Supports defaultValue/defaultFont/legacy default and fixes default-item scroll behavior in the app UI.

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[Salazareo]

@SusTechStitch could you sign the CLA will test this shortly after

[xsourabhsharma]

small thing in UI.js theres a fallback to 'System UI' when nothing is passed, but here defaultFont just ends up undefined since #2896 is about matching app env to web env, shouldnt this default too?

[xsourabhsharma]

hey @Salazareo, the contributor hasnt responded in a while and CLA is still unsigned would it be ok if i take this over and submit a fresh PR with the same fix? dont want it to go stale