Hover states on Delete/Unlink photo controls use colors with insufficient contrast and inconsistent styling

Description:
Two related visual issues were found around the "Delete photo?" confirmation dialog and the photo attachment's delete icon, both involving hover color changes:

Application:
Mergin Maps App: 2026.3.2 - win (62871)
System: Windows 11 Version 25H2

Issue 1 — Delete icon on photo attachment changes color on hover
The delete (trash) icon overlaid on the photo attachment (top-right area of the image) is salmon pink by default. When hovering over it in the desktop app, its background changes to burgundy.

Issue 2 — "Unlink photo" text has poor contrast on hover
The "Unlink photo" text link changes color when hovered over. On hover, the text turns salmon pink, which has poor contrast against the white dialog background — making it hard to read.

Steps to Reproduce (Issue 1):

1. Open a feature form containing a photo attachment field (e.g. "Photo1") in the Mergin Maps desktop application.
2. Locate the delete (trash) icon overlaid on the photo, bottom-right corner of the image.
3. Move the mouse cursor over the delete icon without clicking.

Expected Result: Icon stays salmon pink on hover.
Actual Result: Icon background changes to burgundy on hover.

Steps to Reproduce (Issue 2):

1. Open a feature form containing a photo attachment field (e.g. "Photo1") in the Mergin Maps desktop application.
2. Move the mouse cursor over the "Unlink photo" text link without clicking.

Expected Result: Text remains clearly readable on hover, with sufficient contrast against the white background.
Actual Result: Text changes to salmon pink on hover, which has poor contrast against the white background

Screenshots:

Start from the desktop feature form's photo attachment controls described in the reproduction steps, locating the delete icon and the "Unlink photo" link. Check their default and hover styling, then verify that the icon and link meet the stated expected hover behavior and remain readable against the dialog background.