Ghostty terminal: mouse position offset causes incorrect text selection and click targeting

[dhilgaertner]

Problem

Mouse interactions in the embedded Ghostty terminal are misaligned — the cursor position the terminal registers doesn't match where the user is actually clicking/dragging. This manifests as:

1. Drag-to-select selects wrong text — dragging over visible text highlights a different region than what's under the cursor
2. Double-click doesn't highlight the target word/link — double-clicking on a link or word either selects nothing or selects adjacent content instead
3. General click targeting is off — there appears to be a spatial offset between the macOS mouse position and where Ghostty thinks the click landed

Expected Behavior

• Drag selection should highlight exactly the text under the cursor
• Double-click should select the word or link directly under the pointer
• Click-to-place-cursor should position the terminal cursor at the clicked location

Likely Cause

This is likely a coordinate translation issue between the SwiftUI/AppKit view hierarchy and the Ghostty surface. Common causes:

• Title bar or toolbar offset — if the terminal surface doesn't account for the window's title bar, toolbar, or tab bar height, all coordinates will be shifted vertically
• Retina/scale factor — mismatch between logical points and pixel coordinates on HiDPI displays
• Safe area insets or padding — extra padding around the terminal view not accounted for in hit testing
• SwiftUI view embedding — if Ghostty is embedded via NSViewRepresentable or similar, the coordinate space translation between SwiftUI and the underlying NSView may be incorrect

Reproduction

1. Open any session with a Ghostty terminal containing text
2. Try to select text by clicking and dragging — observe that the selection doesn't match cursor position
3. Double-click on a word or URL — observe it doesn't highlight the expected target