palabras: copyBlock del motor — copia simétrica a pasteAfterBlock

Cierra la deuda del motor «copy = hack de outerHTML». El chrome scrapeaba el
`outerHTML` renderizado del bloque activo (con sus `data-palabras-*`) al
clipboard; ahora hay un comando simétrico que serializa desde el MODELO.

- palabras-provider.svelte.ts: método `copyBlock(index)` (async) — serializa el
  bloque top-level envuelto en un doc de 1 (`serializeHtml` → text/html limpio +
  `renderPalabrasPlainText` → text/plain) y lo escribe al clipboard realm-aware.
  Guard `typeof ClipboardItem` (fallback writeText en realm sin él). Non-mutating
  → funciona read-only. Expuesto en el api snippet + ProviderSnippetProps (types).
- palabras-menubar.svelte: `doCopy` usa `api.copyBlock(loc.path[0])` (fuera el
  `new ClipboardItem/Blob` + outerHTML); gate `!loc`; announce «Bloque copiado».
- palabras-announce.ts: `PALABRAS_ANNOUNCE.copied`.

La serialización (doc de 1 bloque) ya la cubren los tests de serialize-html /
plain-text. Langs es/en de `announce.copied` DIFERIDO (entanglement; ts fallback).

Verificado Playwright (permisos de clipboard): copiar el H1 → clipboard
`text/html` = `<h1>Cómo migrar sin downtime</h1>` LIMPIO (0 `data-palabras-*` →
es serialización del modelo, no scrape), `text/plain` correcto, announce «Bloque
copiado»; 0 errores. Ese HTML limpio es justo lo que pasteAfterBlock parsea →
round-trip simétrico. check 0 errores palabras.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/uix/eidos/components/palabras/palabras-announce.ts

@@ -34,6 +34,7 @@ export const PALABRAS_ANNOUNCE = {
 	movedDown: '#?components.palabras.announce.moved-down|Bloque movido abajo',
 	deleted: '#?components.palabras.announce.deleted|Bloque eliminado',
 	inserted: '#?components.palabras.announce.inserted|Bloque insertado',
+	copied: '#?components.palabras.announce.copied|Bloque copiado',
 	pasted: '#?components.palabras.announce.pasted|Bloque pegado',
 	cellsMerged: '#?components.palabras.announce.cells-merged|Celdas combinadas',
 	cellSplit: '#?components.palabras.announce.cell-split|Celda dividida'

src/uix/eidos/components/palabras/palabras-menubar.svelte

@@ -121,21 +121,12 @@
 		announce(direction === 'up' ? PALABRAS_ANNOUNCE.movedUp : PALABRAS_ANNOUNCE.movedDown);
 	}
 	async function doCopy() {
-		if (!activeEl) return;
-		// targetWindow-aware clipboard (iframe/popup-safe); the ClipboardItem / Blob
-		// constructors are realm-agnostic globals the write accepts.
-		const clipboard = dom.getWindow(content)?.navigator?.clipboard;
-		if (!clipboard) return;
-		try {
-			await clipboard.write([
-				new ClipboardItem({
-					'text/html': new Blob([activeEl.outerHTML], { type: 'text/html' }),
-					'text/plain': new Blob([activeEl.textContent ?? ''], { type: 'text/plain' })
-				})
-			]);
-		} catch {
-			// Clipboard unavailable / permission denied — silently skip.
-		}
+		if (!loc) return;
+		// Serialize the ACTIVE top-level block from the MODEL (clean semantic HTML +
+		// plain text), the symmetric inverse of Pegar — no more scraping rendered
+		// `outerHTML`. Realm-aware clipboard lives in the engine.
+		const ok = await api.copyBlock(loc.path[0]);
+		if (ok) announce(PALABRAS_ANNOUNCE.copied);
 	}
 	function doPaste() {
 		if (!loc) return;
@@ -202,7 +193,7 @@
 					<span>{ts('#?components.palabras.action.move-down|Mover abajo')}</span>
 				</Menubar.Item>
 				<Menubar.Separator />
-				<Menubar.Item disabled={!activeEl} onSelect={doCopy}>
+				<Menubar.Item disabled={!loc} onSelect={doCopy}>
 					<Copy />
 					<span>{ts('#?components.palabras.action.copy|Copiar')}</span>
 				</Menubar.Item>

src/uix/soma/components/palabras/palabras-provider.svelte.ts

@@ -1347,6 +1347,47 @@ export class PalabrasProvider {
 		return changed;
 	}
 
+	/**
+	 * Copy a top-level block to the system clipboard — the symmetric inverse of
+	 * `pasteAfterBlock` (the block-menu "Copy" affordance). Serializes the block
+	 * from the MODEL (`serializeHtml` for `text/html`, `renderPalabrasPlainText`
+	 * for `text/plain`) rather than scraping rendered DOM, so it round-trips
+	 * cleanly back through paste. Returns false when the block / clipboard is
+	 * unavailable or the write is denied. Copy is non-mutating, so it works even
+	 * read-only.
+	 */
+	async copyBlock(index: number): Promise<boolean> {
+		const block = this.document.children[index];
+		if (!block) return false;
+		const target = this.contentRef.current;
+		const win = this.soma.dom.getWindow(target);
+		const clipboard = win?.navigator?.clipboard;
+		if (!win || !clipboard) return false;
+		const oneBlock: PalabrasDocument = { version: this.document.version, children: [block] };
+		const html = serializeHtml(oneBlock);
+		const text = renderPalabrasPlainText(oneBlock);
+		try {
+			// `ClipboardItem` / `Blob` are realm-agnostic globals the clipboard write
+			// accepts (same as the old menubar copy); guarded so soma stays safe in a
+			// non-browser realm (node tests → no ClipboardItem → plain-text fallback).
+			if (typeof ClipboardItem !== 'undefined' && typeof clipboard.write === 'function') {
+				await clipboard.write([
+					new ClipboardItem({
+						'text/html': new Blob([html], { type: 'text/html' }),
+						'text/plain': new Blob([text], { type: 'text/plain' })
+					})
+				]);
+			} else if (typeof clipboard.writeText === 'function') {
+				await clipboard.writeText(text); // no ClipboardItem → plain text only
+			} else {
+				return false;
+			}
+		} catch {
+			return false;
+		}
+		return true;
+	}
+
 	readonly ondragover = (e: DragEvent & { currentTarget: HTMLElement }) => {
 		// Only intercept drags carrying image files; let everything else
 		// (text drags, internal selection drags) follow the browser
@@ -1617,6 +1658,7 @@ export class PalabrasProvider {
 		runCommand: (command: PalabrasCommandName) => this.runCommandName(command),
 		applyCommand: (command: PalabrasCommand) => this.applyCommand(command),
 		pasteAfterBlock: (index: number) => this.pasteAfterBlock(index),
+		copyBlock: (index: number) => this.copyBlock(index),
 		uploadImage: (file: File, apply: (src: string, alt: string | undefined) => void) =>
 			this.uploadImage(file, apply),
 		setCodeLanguage: (language?: string) => this.setCodeLanguage(language),

src/uix/soma/components/palabras/types.ts

@@ -244,6 +244,13 @@ export type PalabrasProviderSnippetProps = {
 	 * the clipboard is empty / unreadable / permission-denied.
 	 */
 	readonly pasteAfterBlock: (index: number) => Promise<boolean>;
+	/**
+	 * Copy the top-level block at `index` to the system clipboard (`text/html`
+	 * from `serializeHtml` + `text/plain`) — the symmetric inverse of
+	 * `pasteAfterBlock`. Serializes from the MODEL, not the DOM. Resolves false
+	 * when the block / clipboard is unavailable or the write is denied.
+	 */
+	readonly copyBlock: (index: number) => Promise<boolean>;
 	/**
 	 * Resolve a picked image `File` to a `src` and hand it to `apply`,
 	 * which writes it into the document (the file-picker counterpart of