feat(builder): media package -- image crop/perf, video size+picker, gallery cols/lightbox, box-model+anim/vis rollout

- ImageBlock/ImageStylePanel: SizeControl width(absorbs old maxWidth
  presets)/height, AspectRatioControl + OBJECT_FIT grid + FocalPointGrid for
  CSS framing crop (aspect-ratio/object-fit/object-position on the <img>).
  Exported <img> always gets loading="lazy" decoding="async", plus width/
  height attrs when the style has a plain px length (pxAttr helper).
- VideoBlock/MediaStylePanel: Video URL text input replaced with
  AssetPicker(mediaType="video") writing videoUrl (paste-URL still handles
  YouTube/Vimeo, upload/browse handle files). Added SizeControl(width) +
  AspectRatioControl so the video frame honors real size/aspect instead of
  a hardcoded 16:9 (padding-bottom hack replaced with CSS aspect-ratio).
  New optional `poster` prop (image AssetPicker) + preload="metadata" on
  file-type <video>.
- Gallery: surfaced the existing-but-unexposed `columns` and `lightbox`
  props with panel controls.
- All 5 owned components (ImageBlock, VideoBlock, Gallery, ContentSlider,
  MapEmbed): added margin/padding (per-side)/border/box-shadow/opacity style
  defaults + AnimationControl/VisibilityControl-backed animation/
  animationDelay/hideOnDesktop/hideOnTablet/hideOnMobile props. New shared
  mediaBoxModel.tsx (package-local, not shared.tsx) DRYs the box-model +
  border/effects + animation/visibility panel sections across
  ImageStylePanel and MediaStylePanel.
- Tests: extended *.toHtml.test.ts for all 5 components (crop/perf attrs,
  video size/aspect/poster/preload, gallery columns/lightbox, box-model
  style emission, craft.props presence) + new MediaStylePanel.video.test.tsx
  verifying the AssetPicker wiring writes videoUrl/poster and the video-only
  size controls are gated on videoUrl. 694 tests green, tsc + vite build
  clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

craft/src/components/media/ImageBlock.toHtml.test.ts

@@ -1,5 +1,5 @@
 import { describe, test, expect } from 'vitest';
-import { ImageBlock } from './ImageBlock';
+import { ImageBlock, pxAttr } from './ImageBlock';
 
 const toHtml = (ImageBlock as any).toHtml;
 
@@ -32,3 +32,95 @@ describe('ImageBlock.toHtml src/alt XSS hardening', () => {
     expect(html).toContain('alt="A photo"');
   });
 });
+
+describe('ImageBlock.toHtml perf attributes (always emitted)', () => {
+  test('loading="lazy" and decoding="async" are always present', () => {
+    const { html } = toHtml({ src: 'https://example.com/photo.jpg' }, '');
+    expect(html).toContain('loading="lazy"');
+    expect(html).toContain('decoding="async"');
+  });
+
+  test('width/height attributes are emitted when the style has plain px values', () => {
+    const { html } = toHtml({ src: 'https://example.com/photo.jpg', style: { width: '400px', height: '300px' } }, '');
+    expect(html).toContain('width="400"');
+    expect(html).toContain('height="300"');
+  });
+
+  test('width/height attributes are omitted when the style value is not a plain px length', () => {
+    const { html } = toHtml({ src: 'https://example.com/photo.jpg', style: { width: '50%', height: 'auto' } }, '');
+    expect(html).not.toMatch(/\swidth="/);
+    expect(html).not.toMatch(/\sheight="/);
+  });
+});
+
+describe('pxAttr', () => {
+  test('extracts the numeric portion of a plain px length', () => {
+    expect(pxAttr('400px')).toBe('400');
+    expect(pxAttr('12.5px')).toBe('12.5');
+  });
+
+  test('returns undefined for non-px units, non-string, or unset values', () => {
+    expect(pxAttr('50%')).toBeUndefined();
+    expect(pxAttr('auto')).toBeUndefined();
+    expect(pxAttr(undefined)).toBeUndefined();
+    expect(pxAttr(400)).toBeUndefined();
+  });
+});
+
+describe('ImageBlock.toHtml CSS framing crop (aspect-ratio + object-fit + object-position)', () => {
+  test('style.aspectRatio, objectFit, objectPosition all flow into the emitted style attribute', () => {
+    const { html } = toHtml(
+      { src: 'https://example.com/photo.jpg', style: { aspectRatio: '16 / 9', objectFit: 'cover', objectPosition: 'center top' } },
+      ''
+    );
+    expect(html).toContain('aspect-ratio:16 / 9');
+    expect(html).toContain('object-fit:cover');
+    expect(html).toContain('object-position:center top');
+  });
+});
+
+describe('ImageBlock.toHtml box-model styles (margin/padding/border/shadow/opacity)', () => {
+  test('margin/padding/border/box-shadow/opacity all flow into the emitted style attribute', () => {
+    const { html } = toHtml(
+      {
+        src: 'https://example.com/photo.jpg',
+        style: {
+          marginTop: '10px', marginRight: '10px', marginBottom: '10px', marginLeft: '10px',
+          paddingTop: '5px',
+          border: '2px solid #ff0000',
+          boxShadow: '0 4px 8px rgba(0,0,0,0.12)',
+          opacity: '0.8',
+        },
+      },
+      ''
+    );
+    expect(html).toContain('margin-top:10px');
+    expect(html).toContain('padding-top:5px');
+    expect(html).toContain('border:2px solid #ff0000');
+    expect(html).toContain('box-shadow:0 4px 8px rgba(0,0,0,0.12)');
+    expect(html).toContain('opacity:0.8');
+  });
+});
+
+describe('ImageBlock.craft.props exposes the box-model/animation/visibility rollout', () => {
+  test('animation, animationDelay, hideOnDesktop/Tablet/Mobile are present with blank/false defaults', () => {
+    const props = (ImageBlock as any).craft.props;
+    expect(props.animation).toBe('');
+    expect(props.animationDelay).toBe('0');
+    expect(props.hideOnDesktop).toBe(false);
+    expect(props.hideOnTablet).toBe(false);
+    expect(props.hideOnMobile).toBe(false);
+  });
+
+  test('style carries blank/default box-model and crop keys', () => {
+    const style = (ImageBlock as any).craft.props.style;
+    expect(style).toHaveProperty('aspectRatio');
+    expect(style).toHaveProperty('objectFit');
+    expect(style).toHaveProperty('objectPosition');
+    expect(style).toHaveProperty('marginTop');
+    expect(style).toHaveProperty('paddingTop');
+    expect(style.border).toBe('none');
+    expect(style.boxShadow).toBe('none');
+    expect(style.opacity).toBe('1');
+  });
+});