feat(words): internal scroll for the content area + capture-phase scroll sync

The editor body was unbounded vertically — long documents pushed the
whole page instead of confining the scroll to the editor surface.
Per spec: "la parte de la edicion deberia tener un scroll".

Recipe:
- Three new tokens `content-max-block-size-sm/md/lg` (50vh / 60vh /
  70vh) mirror the existing `content-min-block-size-*`. Generated CSS
  regenerated.

CSS:
- `[data-words-content]` now carries `max-block-size:
  var(--_words-content-max-block-size)` and `overflow-y: auto`. The
  min-block-size baseline stays as the starting height for empty
  editors. When content grows past the cap, the body scrolls
  internally — the host card no longer balloons.
- `scroll-padding-block: 1rem` hint so caret-into-view nudges leave
  breathing room.

Block-handle / block-inserter / image-float-bar:
- Switch scroll listeners from `window.addEventListener('scroll')` to
  `document.addEventListener('scroll', { capture: true })`. Scroll
  events don't bubble; the previous wiring only caught window scrolls.
  Now the gutter overlays (handle position, "+" snap target, image
  float bar anchor) re-measure when the user scrolls INSIDE the
  content area too.

Verification: dev probe at /uix/components/words confirms
`max-block-size: 600px`, `overflow-y: auto`, content scrollHeight
(615px) > clientHeight (600px), `isInternallyScrollable: true` on a
1000px viewport (60vh of 1000 = 600). 467/467 tests pass across
eidos + morfo + sema + soma/components/words.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/uix/eidos/components/words/words-block-handle.svelte

@@ -220,12 +220,17 @@
 
 		const win = content.ownerDocument.defaultView;
 		const onscroll = () => measureFromEl(hoverBlockEl);
-		win?.addEventListener('scroll', onscroll, { passive: true });
+		// Capture-phase + on document so we also catch scrolls inside
+		// any scrollable ancestor (the content area itself now has
+		// overflow-y:auto). Scroll events do not bubble, so a plain
+		// `document.addEventListener('scroll')` without capture would
+		// only catch root-document scrolls.
+		document.addEventListener('scroll', onscroll, { capture: true, passive: true });
 		win?.addEventListener('resize', onscroll, { passive: true });
 
 		return () => {
 			document.removeEventListener('mousemove', onmove);
-			win?.removeEventListener('scroll', onscroll);
+			document.removeEventListener('scroll', onscroll, { capture: true });
 			win?.removeEventListener('resize', onscroll);
 		};
 	});

src/uix/eidos/components/words/words-block-inserter.svelte

@@ -223,14 +223,18 @@
 			// on scroll and let the next mousemove re-snap.
 			seam = null;
 		};
-		win?.addEventListener('scroll', onscroll, { passive: true });
+		// Capture phase so we catch scrolls inside the content area
+		// (which now scrolls internally) — scroll events do not bubble,
+		// so plain document.addEventListener would only catch root
+		// scrolls.
+		document.addEventListener('scroll', onscroll, { capture: true, passive: true });
 		win?.addEventListener('resize', onscroll, { passive: true });
 
 		return () => {
 			document.removeEventListener('mousemove', onmove);
 			document.removeEventListener('dragover', ondragover);
 			document.removeEventListener('drop', ondrop);
-			win?.removeEventListener('scroll', onscroll);
+			document.removeEventListener('scroll', onscroll, { capture: true });
 			win?.removeEventListener('resize', onscroll);
 		};
 	});

src/uix/eidos/components/words/words-image-float-bar.svelte

@@ -63,12 +63,16 @@
 		const win = targetFigure.ownerDocument.defaultView;
 		if (!win) return;
 		const opts: AddEventListenerOptions = { passive: true };
-		win.addEventListener('scroll', measure, opts);
+		// Capture-phase on document catches scrolls inside the content
+		// area (now overflow-y:auto) too — scroll events don't bubble
+		// so plain `win.addEventListener('scroll')` only catches the
+		// root document scroll.
+		document.addEventListener('scroll', measure, { capture: true, passive: true });
 		win.addEventListener('resize', measure, opts);
 		const ro = new ResizeObserver(measure);
 		ro.observe(targetFigure);
 		return () => {
-			win.removeEventListener('scroll', measure, opts);
+			document.removeEventListener('scroll', measure, { capture: true });
 			win.removeEventListener('resize', measure, opts);
 			ro.disconnect();
 		};

src/uix/eidos/components/words/words.css

@@ -4,6 +4,7 @@
 	--_words-content-px: var(--words-content-px-md);
 	--_words-content-py: var(--words-content-py-md);
 	--_words-content-min-block-size: var(--words-content-min-block-size-md);
+	--_words-content-max-block-size: var(--words-content-max-block-size-md);
 	/* Gutter reserved for the block-handle grip + inserter "+" overlay.
 	   Rendered as a SEPARATE column outside the editor box (its own
 	   background + dot pattern), with a small gap before the editor.
@@ -87,6 +88,7 @@
 	--_words-content-px: var(--words-content-px-sm);
 	--_words-content-py: var(--words-content-py-sm);
 	--_words-content-min-block-size: var(--words-content-min-block-size-sm);
+	--_words-content-max-block-size: var(--words-content-max-block-size-sm);
 	--_words-toolbar-px: var(--words-toolbar-px-sm);
 	--_words-toolbar-py: var(--words-toolbar-py-sm);
 	--_words-button-size: var(--words-button-size-sm);
@@ -99,6 +101,7 @@
 	--_words-content-px: var(--words-content-px-lg);
 	--_words-content-py: var(--words-content-py-lg);
 	--_words-content-min-block-size: var(--words-content-min-block-size-lg);
+	--_words-content-max-block-size: var(--words-content-max-block-size-lg);
 	--_words-toolbar-px: var(--words-toolbar-px-lg);
 	--_words-toolbar-py: var(--words-toolbar-py-lg);
 	--_words-button-size: var(--words-button-size-lg);
@@ -1828,7 +1831,12 @@
 }
 
 [data-words-content] {
+	/* Starting baseline keeps the editor at a sensible height when
+	 * empty; max-block-size caps growth so long documents scroll
+	 * INSIDE the content area instead of pushing the page. */
 	min-block-size: var(--_words-content-min-block-size);
+	max-block-size: var(--_words-content-max-block-size);
+	overflow-y: auto;
 	padding-block: var(--_words-content-py);
 	padding-inline: var(--_words-content-px);
 	color: var(--words-content-color);
@@ -1838,6 +1846,10 @@
 	caret-color: var(--_words-accent-solid);
 	user-select: text;
 	-webkit-user-select: text;
+	/* Hint to the browser that this is a self-contained scroll region
+	 * so the rail / drawer overlays positioned by viewport coords don't
+	 * get clipped weirdly on focus. */
+	scroll-padding-block: 1rem;
 }
 
 [data-words-content] * {

src/uix/eidos/generated/base.css

@@ -2279,6 +2279,9 @@
 	--words-content-min-block-size-sm: 10rem;
 	--words-content-min-block-size-md: 13rem;
 	--words-content-min-block-size-lg: 16rem;
+	--words-content-max-block-size-sm: 50vh;
+	--words-content-max-block-size-md: 60vh;
+	--words-content-max-block-size-lg: 70vh;
 	--words-selection-color: var(--color-content-primary);
 	--words-block-gap: var(--space-2);
 	--words-heading-color: var(--color-content-primary);

src/uix/eidos/lib/recipes/base.ts

@@ -2715,6 +2715,9 @@ export const THEME_BASE_RECIPE_TOKENS = {
 		'content-min-block-size-sm': '10rem',
 		'content-min-block-size-md': '13rem',
 		'content-min-block-size-lg': '16rem',
+		'content-max-block-size-sm': '50vh',
+		'content-max-block-size-md': '60vh',
+		'content-max-block-size-lg': '70vh',
 		'selection-color': 'var(--color-content-primary)',
 		'block-gap': 'var(--space-2)',
 		'heading-color': 'var(--color-content-primary)',