task(ios): auto-focus the site URL field when adding a site

[dcalhoun]

What?

Auto-focus the site URL field when adding a site in the iOS demo app.

Why?

Improved UX and quicker to use.

How?

Conditionally auto-focus the field via a new state variable.

Testing Instructions

1. Launch the iOS demo app
2. Tap Add WordPress Site
3. Verify the site URL input is focused

Accessibility Testing Instructions

N/A, unnecessary for the demo app.

Screenshots or screencast

Screen.Recording.iPhone.18.Pro.10-14-2026.at.10.52.32.mp4

---

AI-generated details

Focuses the Site URL field when the iOS demo app's "Add WordPress Site" sheet opens, matching the Android demo app.

Uses @FocusState + .focused(_:), set in .onAppear. .defaultFocus(_:_:) (iOS 17+) was tried and did not focus the field in the sheet on the iOS 27 simulator.

Testing: launch the iOS demo app, open the add-site sheet, and confirm the Site URL field has a cursor (toggle the software keyboard with ⇧⌘K in the simulator if needed).

🤖 Generated with Claude Code

[wpmobilebot]

XCFramework Build

This PR's XCFramework is available for testing. Add the following to your Package.swift:

.package(url: "https://github.com/wordpress-mobile/GutenbergKit", branch: "pr-build/787")

_{Built from 089d761}