fix: stabilize mobile graph dragging and resize

tests/graph-renderer-utils.mjs

@@ -0,0 +1,29 @@
+import assert from "node:assert/strict";
+
+import {
+  isUsableGraphCanvasSize,
+  remapPositionBetweenRects,
+} from "../ui/graph-renderer-utils.js";
+
+assert.equal(isUsableGraphCanvasSize(0, 0), false);
+assert.equal(isUsableGraphCanvasSize(47, 120), false);
+assert.equal(isUsableGraphCanvasSize(120, 47), false);
+assert.equal(isUsableGraphCanvasSize(48, 48), true);
+assert.equal(isUsableGraphCanvasSize(320, 180), true);
+
+assert.deepEqual(
+  remapPositionBetweenRects(60, 35, { x: 10, y: 10, w: 100, h: 50 }, { x: 20, y: 20, w: 200, h: 100 }),
+  { x: 120, y: 70 },
+);
+
+assert.deepEqual(
+  remapPositionBetweenRects(-50, 300, { x: 10, y: 10, w: 100, h: 50 }, { x: 20, y: 20, w: 200, h: 100 }),
+  { x: 20, y: 120 },
+);
+
+assert.deepEqual(
+  remapPositionBetweenRects(42, 84, null, { x: 20, y: 20, w: 200, h: 100 }),
+  { x: 42, y: 84 },
+);
+
+console.log("graph-renderer-utils tests passed");