build: go 1.24

We were running behind and there were quite some deprecations to update.
This was mostly in the upstream copy/pasta package but seems quite
minimal.

vendor/github.com/charmbracelet/x/cellbuf/geom.go

@@ -0,0 +1,21 @@
+package cellbuf
+
+import (
+	"image"
+)
+
+// Position represents an x, y position.
+type Position = image.Point
+
+// Pos is a shorthand for Position{X: x, Y: y}.
+func Pos(x, y int) Position {
+	return image.Pt(x, y)
+}
+
+// Rectange represents a rectangle.
+type Rectangle = image.Rectangle
+
+// Rect is a shorthand for Rectangle.
+func Rect(x, y, w, h int) Rectangle {
+	return image.Rect(x, y, x+w, y+h)
+}