Transform: scale, rotation and mirror as properties, world transform as a matrix chain, oriented colliders (#76)

Four new rows on sprite, text, collider and container (block TRANSFORM):
scale, rotation in degrees clockwise, mirrorX, mirrorY. As properties they
get override/reset/apply, loading of old projects, write-back after play and
the Properties node for free; camera and behavior have none.

The hierarchy composes T*R*S per level (composeAlongChain replaces
sumAlongChain), so children rotate and scale with their parent. Reparenting
and grouping keep the look (carriedTransform). Drawing goes through
placeNode, the gizmo is a polygon, cull and objectRect use the AABB, drags
are computed in the parent's system.

Colliders are oriented boxes: SAT for box/box, box-circle in the box frame;
exitDistance replaces axisSeparation/axisCorrection, moveAndSlide moves along
the object's own axes.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tools/e2e/lib/pictures.mjs

@@ -0,0 +1,19 @@
+/** A 32 px picture, red on the left and green on the right, pasted in for pixel checks (28l, 29e). */
+export const PASTE_HALVES = `(async () => {
+  const canvas = document.createElement('canvas');
+  canvas.width = 32;
+  canvas.height = 32;
+  const g = canvas.getContext('2d');
+  g.fillStyle = '#e63c3c'; g.fillRect(0, 0, 16, 32);
+  g.fillStyle = '#3cc85a'; g.fillRect(16, 0, 16, 32);
+  const blob = await new Promise((resolve) => canvas.toBlob(resolve, 'image/png'));
+  const transfer = new DataTransfer();
+  transfer.items.add(new File([blob], 'halves.png', { type: 'image/png' }));
+  window.dispatchEvent(new ClipboardEvent('paste', { clipboardData: transfer, bubbles: true }));
+})()`;
+export const HALVES_LEFT = '#e63c3c';
+export const HALVES_RIGHT = '#3cc85a';
+
+/** The pasted picture's asset, once the paste has landed. */
+export const FIND_HALVES =
+  "__gm.state.project.assets.filter((a) => a.type === 'texture' && a.width === 32 && a.height === 32).map((a) => ({ id: a.id, file: a.file }))[0] ?? null";

tools/e2e/lib/scaffold.mjs

@@ -16,6 +16,7 @@ export const LANES = {
   keyRepeat: -300,
   stateMachine: -700,
   console: -1100,
+  transform: -1500,
 };
 
 /**