feat(words): inline heading-level control in the Block drawer panel

Adds an H1/H2/H3 toggle to the drawer's Block panel, shown only when
the caret is in a heading (currentBlock === 'heading'). The toggle
reflects currentHeadingLevel and dispatches the structured
`setBlock` command with the numeric level via applyCommand:

  applyCommand({ type: 'setBlock', block: 'heading', level })

runCommand / WordsCommandName has no per-level id (heading-1/2/3 are
slash/insert-menu ids), so the structured command carries the level;
`as const` keeps each level a 1|2|3 literal.

Verified in browser: caret in a heading shows "Heading level"; the
toggle reflects the active level and converts bidirectionally
(H1→H3→H2) with the toggle updating. npm run check: 0 errors.

Also closes the stale "drag handle outside the rail over <code>" P1:
it does not reproduce — the rail was removed in the gutter redesign
(5450d5f7) and the handle now anchors to contentRect.left+8 for every
block type (verified: identical left over code and paragraph). Both
P1 items marked resolved in continue.md.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

continue.md

@@ -148,21 +148,31 @@ panel renderiza los 4 controles nuevos; click en swatch de Background
 actualiza el figure (`background-color:#22c55e`) preservando
 radius/border/shadow (shallow-merge correcto). `npm run check` 0 errors.
 
-## Pendiente para mañana
-
-### P1 — Drag handle FUERA del rail sobre bloques `<code>` (heredado)
-
-El grip se va fuera de la rail al hacer hover sobre un code block.
-Sin diagnosticar. Lugar: `eidos/components/words/words-block-handle.svelte
-> measureFromEl()`. Pasos: comparar `getBoundingClientRect().left` de
-`<pre>` vs `<p>`; si difieren, buscar padding/margin/transform en
-`[data-words-content] :where(pre)` en `words.css`.
+### ✅ P1 — Drag handle sobre `<code>` (NO reproduce)
+
+Investigado: NO reproduce en el código actual. El "rail" al que se
+refería el bug fue ELIMINADO en el rediseño de gutter (commit
+`5450d5f7`, "rail out"), posterior al sprint EV donde se reportó.
+`measureFromEl` (`words-block-handle.svelte`) ancla el handle a
+`contentRect.left + 8` — block-type-agnostic. Verificado en browser:
+sobre code y sobre paragraph el gutter cae en `left: 350.333` idéntico
+(solo difiere `top`). No hay nada que arreglar; bug obsoleto.
+
+### ✅ P1 — Heading inline level change (h1 ↔ h2 ↔ h3)
+
+Añadido al Block panel del drawer
+(`eidos/components/words/words-drawer.svelte > blockPanel`): cuando
+`currentBlock === 'heading'`, un ToggleGroup H1/H2/H3 (value =
+`currentHeadingLevel`) despacha `applyCommand({ type: 'setBlock',
+block: 'heading', level })`. `runCommand` / `WordsCommandName` no tiene
+id por-nivel (`heading-1/2/3` son ids de slash / insert-menu), por eso
+se usa el comando estructurado `setBlock` con el nivel numérico (`as
+const` mantiene cada `level` como literal 1|2|3). Verificado en
+browser: caret en heading → el panel muestra "Heading level"; el toggle
+refleja el nivel actual; el click convierte bidireccional (H1→H3→H2) y
+el toggle se actualiza. `npm run check` 0 errors.
 
-### P1 — Heading inline level change (h1 ↔ h2 ↔ h3) (heredado)
-
-Cambiar nivel de heading inline sin abrir drawer. Recomendación:
-empezar por el Block panel del drawer (verificar que el HeadingPicker
-se muestra cuando `currentBlock === 'heading'`).
+## Pendiente para mañana
 
 ### P2 — Heredados
 

src/uix/eidos/components/words/words-drawer.svelte

@@ -196,6 +196,15 @@
 		{ id: 'align-right', label: '⫸' },
 		{ id: 'align-justify', label: '☷' }
 	] as const satisfies readonly { id: WordsCommandName; label: string }[];
+
+	// Heading level uses the structured `setBlock` command (carries the
+	// numeric level) — `runCommand` / WordsCommandName has no per-level
+	// id. `as const` keeps each `level` a 1|2|3 literal for the command.
+	const HEADING_LEVEL_ACTIONS = [
+		{ level: 1, value: '1', label: 'H1', title: 'Heading 1' },
+		{ level: 2, value: '2', label: 'H2', title: 'Heading 2' },
+		{ level: 3, value: '3', label: 'H3', title: 'Heading 3' }
+	] as const;
 </script>
 
 <Words.Drawer bind:open {defaultOpen} {disabled} {...rest} data-side={side}>
@@ -530,6 +539,26 @@
 {/snippet}
 
 {#snippet blockPanel(s: ProviderSnippetProps)}
+	{#if s.currentBlock === 'heading'}
+		<div data-words-drawer-section-subtitle>Heading level</div>
+		<ToggleGroup
+			type="single"
+			size="sm"
+			variant="ghost"
+			value={s.currentHeadingLevel ? [String(s.currentHeadingLevel)] : []}
+			onValueChange={(next) => {
+				const action = HEADING_LEVEL_ACTIONS.find((a) => a.value === next[0]);
+				if (action) s.applyCommand({ type: 'setBlock', block: 'heading', level: action.level });
+			}}
+			aria-label="Heading level"
+		>
+			{#each HEADING_LEVEL_ACTIONS as h (h.value)}
+				<ToggleGroup.Item value={h.value} title={h.title} onmousedown={(e) => e.preventDefault()}>
+					{h.label}
+				</ToggleGroup.Item>
+			{/each}
+		</ToggleGroup>
+	{/if}
 	<div data-words-drawer-section-subtitle>Text align</div>
 	<ToggleGroup
 		type="single"