Make Status Center resizable and remember size

[vishg13]

This improves the Status Center usability:

• Adds a resize grip (Thumb) to the Status Center
• Enforces sensible MinWidth/MinHeight
• Persists width/height in local settings and restores on load

How to verify:

1. Start a copy/move to open the Status Center
2. Drag the bottom edge/corner to resize
3. Close and reopen → size persists

Notes:

• Keys: StatusCenterWidth / StatusCenterHeight
• Happy to move persistence to the project settings service if preferred

Fixes #14438

[yaira2]

@vishg13 thank you for the PR. This implementation seems to be different than what was discussed in #14438. To be fair, the original proposal still had the old requirements, and we should have updated that from our end. Would you like to continue working on this to meet the finished requirements?