chore: update minimum compiler version to 0.15.0

CeTZ 0.5.2 requires 3D coordinate vectors (x, y, z) for raw
coordinate tuples passed to coordinate.resolve(). Update internal
wire computations (dodge, guided) to use 3-element tuples, fix
.last() to .at(1) for y-component access on resolved coordinates,
and add a normalize-coord utility that automatically pads user-
provided 2D points (x, y) to (x, y, 0) so users do not need to
specify the z dimension.

README.md

@@ -3,7 +3,7 @@
 Circuiteria is a [Typst](https://typst.app) package for drawing block circuit diagrams using the [CeTZ](https://typst.app/universe/package/cetz) package.
 
 <p align="center">
-  <img src="./gallery/platypus.png" alt="A platypus / Perry the Platypus meme made with colored rounded rectangles">
+  <img src="./gallery/platypus.png" alt="Perry the platypus" alt="A platypus / Perry the Platypus meme made with colored rounded rectangles">
 </p>
 
 ## Examples

src/wire.typ

@@ -314,7 +314,7 @@
   if name != none {
     let names = ()
     
-    if type(name) == str or type(name) == content {
+    if type(name) == str {
       names = ((name, name-pos),)
       
     } else if type(name) == array {