Focused text fields show their outline on every edge (#202)

The focus outline of a text field was only visible at its corners.
The mask that clips the text covered the whole field, border included,
so the 1 px stroke was cut away along every straight edge. Only the
rounded corners bent inwards far enough to survive. With the larger
radius the new theme tried, this became obvious.

- TextField puts text, selection and caret into their own container.
  Only that container is masked. Background and outline are not.
- NumberField and the rename field in lists inherit the fix.
- The theme radius goes back to 2 px.
- New debug hook __gm.focusedRect() returns where the focused widget
  sits, so a check can read its border.

Tests:
- ./check.sh: 141 files, 2080 tests, exit 0
- GM_STEPS=2: ALL PASSED, 24 checks (one new)
- The new check in 2c reads the middle of all four edges of the
  focused name field. All four must be the focus blue.
- Counter-check with the old full-field mask: the check fails, all
  four edges read #24272e.
- Editor check total is now 1286 (1285 + 1), computed, not measured.

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

src/ui/widgets/TextField.ts

@@ -1,4 +1,4 @@
-import { CanvasTextMetrics, type FederatedPointerEvent, Graphics, Text } from 'pixi.js';
+import { CanvasTextMetrics, Container, type FederatedPointerEvent, Graphics, Text } from 'pixi.js';
 import { pressCount } from '../clicks';
 import { drawControlBox } from '../draw';
 import type { TextEditTarget } from '../KeyboardBridge';
@@ -66,15 +66,12 @@ export class TextField extends Widget implements TextEditTarget {
     this.minWidth = options.width ?? 80;
     this.textNode = new Text({ text: value, style: textStyle(options.style ?? 'body') });
     this.placeholderNode = new Text({ text: this.placeholder, style: textStyle('muted') });
-    this.addChild(
-      this.bg,
-      this.selectionShape,
-      this.placeholderNode,
-      this.textNode,
-      this.caret,
-      this.clipShape,
-    );
-    this.mask = this.clipShape;
+    // Only the contents are clipped: a mask on the whole field cut its border away along the
+    // straight edges and left it showing at the rounded corners alone.
+    const content = new Container();
+    content.addChild(this.selectionShape, this.placeholderNode, this.textNode, this.caret);
+    content.mask = this.clipShape;
+    this.addChild(this.bg, content, this.clipShape);
 
     this.trackHover();
     this.on('pointerdown', (e: FederatedPointerEvent) => this.handlePointerDown(e));