Fix ShrinkTo computing a wrong bottom edge

[SQReder]

Context

TilingService.ShrinkTo centers a fixed-size rectangle inside a container. It is used to place windows that cannot be resized. The bottom edge was computed as container.Height - wdiff / 2 — the container height instead of its bottom, and the width difference instead of the height difference — so those windows were given a bogus target rectangle.

Changes

• Derive the right and bottom edges from the requested size (left + width, top + height), so the size is preserved exactly, including when the size difference is odd.

Verification

• dotnet build FancyWM.GUI (Release) — 0 errors.
• Not exercised at runtime with an unresizable window; unit tests were not run locally.

Risks

• None known. The change is confined to the unresizable-window branch of CalculateRepositionTargets.

🤖 Generated with Claude Code

[github-actions]

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