PICARD-3178: Initialize resize widget states on options page load

[zas]

Set QGroupBox checked state after configuring child widgets to ensure proper enable/disable state. Call _resize_mode_changed() to initialize width/height widget visibility based on selected resize mode.

Summary

• This is a…
  • Bug fix
  • Feature addition
  • Refactoring
  • Minor / simple change (like a typo)
  • Other
• Describe this change in 1-2 sentences:

Problem

• JIRA ticket (optional): PICARD-3178

Solution

Action

Additional actions required:

• Update Picard documentation (please include a reference to this PR)
• Other (please specify below)

[phw]

LGTM

[rdswift]

Great, thanks.