Fix mobile search modal interaction

[RabbiIslamRony]

PR Type

What kind of change does this PR introduce?

• Bugfix
• Security fix
• Improvement
• New Feature
• Refactoring (no functional changes, no api changes)
• Build related changes
• Text changes
• Other... Please describe:

Description

How to reproduce the issue or how to test the changes

1. On a mobile viewport, open a Directorist archive search modal or the Search Modal block and confirm the current panel is difficult to dismiss, can exceed the usable viewport, and uses sub-16px search controls.
2. Check out this branch and run npm run build-legacy and npm run build:blocks.
3. At 575px or below, open each search modal and confirm it is anchored to the bottom, capped at 80dvh, uses safe-area spacing, and scrolls its form content internally when necessary.
4. Confirm the visible 44px close control, overlay click, Escape key, and a downward swipe from the sheet header/handle all dismiss the modal.
5. Confirm the first real search field receives focus at 16px, tapping it does not open a nested modal, and closing restores both the trigger focus and the original page scroll position.
6. At desktop widths, confirm the Search Modal block retains its existing top-popup presentation.

LocalWP verification covered 390x844, 390x500, 390x350, and 1280x800 viewports in Chromium. Physical iPhone Safari and Android Chrome sign-off is still required before release because those devices were not available in this environment.

Any linked issues

Fixes #2326

Checklist

• My code follows the WordPress coding standards

[RabbiIslamRony]

The PHPCS check fails before checkout because the base branch still runs fork code through pull_request_target; Actions refuses the checkout before this PR code executes. PR #2945 replaces that workflow with the safe pull_request event. Local changed-file PHP syntax/PHPCS, both production builds, and git diff --check passed.