test(editor): cover AcroForm controls in FormFieldsOverlay

[McanKul]

The AcroForm backend has broad coverage, but the React overlay that maps PDF fields to HTML controls has no focused component test.

Scope:

• Cover text, multiline, checkbox, radio, combo and list controls.
• Verify existing values and the onChange(name, value) payload.
• Verify read-only and hidden fields cannot be edited.
• Verify page filtering and fields without a usable rectangle.
• Keep the test independent from the Tauri runtime.

Acceptance criteria:

• Add a focused FormFieldsOverlay test suite.
• Tests cover the control types and edge cases above.
• Production behavior only changes if a test exposes a real bug.

[RaviAnand111]

I am working on this @McanKul, Can you please assign this to me.

[McanKul]

Great, issue #67 is assigned to you. Please start from the latest development branch and open the PR against development. Keep the change focused on the FormFieldsOverlay tests: control types, existing values, onChange payloads, read-only/hidden fields, page filtering, and unusable rectangles. Keep the suite independent from Tauri; production behavior should only change if a test exposes a real bug. Please include the targeted test, full test suite, and build results in the PR, and feel free to ask if anything is unclear.