Add a decimals option, fix dropdown overflow and the texture filter

- NumberField takes a decimals option (default 3); frame rects and the
  slice dialog use 0, matching their integer model.
- Button truncates its label to the drawn width; Dropdown reserves the
  chevron slot. NodeView reuses the shared truncate().
- Setting scaleMode leaves the style's shared resource id in place, so
  the old GPU sampler stayed in use until a reload. Call style.update().
- Graph gets a header bar like the Texture tab: GraphEditor is now the
  frame, the former editor is GraphCanvas. A selection the tab does not
  concern no longer unloads the behavior.
- New e2e step 14 guards text overflow across all widgets.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/editor/texture/SliceDialog.ts

@@ -90,6 +90,8 @@ export class SliceDialog extends Popup {
     const field = new NumberField(this.options[key], {
       min,
       step: 1,
+      // Counts of cells and pixel offsets; the value is rounded on change, so 0 hides nothing.
+      decimals: 0,
       onChange: (value) => {
         this.options[key] = Math.round(Number(value));
         this.refreshSummary();