refactor(words): close audit debt D1 (honest cast) + D2 (dedup image picker)

- D1 (soma) block-tree.ts:104 — replace `doc as never` (which disabled all
  type checking on the descend container) with `doc as unknown as {...}`, the
  honest cast that still asserts the permissive descend-node shape
  childStacks() reads.

- D2 (eidos) — extract the duplicated ~25-line "file picker → FileReader →
  data URL" flow (copy-pasted in words-block-gutter.svelte and
  words-block-panel.svelte) into a shared `pickImageFile(doc, onPick)` helper
  in words-image-file.ts. Both consumers now call it; zero inline FileReader
  blocks remain. Kept as a plain helper (not ActiveDom) — a transient
  <input type=file> + FileReader is not instrumented by active-dom, so a
  direct Document touch is correct; the caller resolves the right Document.

Gates: npm run check 1 error (pre-existing grafito, not Words) · words soma
452/452 · prettier clean.

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

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

@@ -26,6 +26,7 @@
 		type ProviderSnippetProps,
 		type WordsBlockMenuEntry
 	} from '$soma/components/words';
+	import { pickImageFile } from './words-image-file';
 
 	let {
 		api,
@@ -206,32 +207,13 @@
 	// until the user picks a file or types a URL). The gutter inserter
 	// opens a file picker → FileReader → data URL when an image entry
 	// is selected, then inserts the block with a valid `src`. URLs from
-	// real backends would replace this with a fetch + upload.
+	// real backends would replace this with a fetch + upload. The picker
+	// flow is shared with the inspector's image panel (`pickImageFile`).
 	function insertImageInteractive() {
 		const doc =
-			(typeof document !== 'undefined' ? document : null) ??
-			content?.ownerDocument ??
-			null;
+			(typeof document !== 'undefined' ? document : null) ?? content?.ownerDocument ?? null;
 		if (!doc) return;
-		const input = doc.createElement('input');
-		input.type = 'file';
-		input.accept = 'image/*';
-		input.style.display = 'none';
-		input.addEventListener('change', () => {
-			const file = input.files?.[0];
-			input.remove();
-			if (!file) return;
-			const reader = new FileReader();
-			reader.onload = () => {
-				const src = typeof reader.result === 'string' ? reader.result : '';
-				if (!src) return;
-				const alt = file.name.replace(/\.[^/.]+$/, '') || undefined;
-				insert({ type: 'image', src, alt });
-			};
-			reader.readAsDataURL(file);
-		});
-		doc.body.appendChild(input);
-		input.click();
+		pickImageFile(doc, (src, alt) => insert({ type: 'image', src, alt }));
 	}
 
 	function handleInsert(entry: WordsBlockMenuEntry) {
@@ -303,7 +285,8 @@
 	{#if inGutter || menuOpen}
 		<div
 			data-words-block-outline
-			style="top: {rect.top - 3}px; left: {rect.left - 3}px; width: {rect.width + 6}px; height: {rect.height + 6}px;"
+			style="top: {rect.top - 3}px; left: {rect.left - 3}px; width: {rect.width +
+				6}px; height: {rect.height + 6}px;"
 		></div>
 	{/if}
 	<!-- Center the handle vertically against the block's height: position

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

@@ -31,6 +31,7 @@
 	import Toggle from '$uix/eidos/components/toggle';
 	import { Switch } from '$uix/eidos/components/switch';
 	import WordsColorRow from './words-color-row.svelte';
+	import { pickImageFile } from './words-image-file';
 	import {
 		TextAlignStart,
 		TextAlignCenter,
@@ -434,36 +435,20 @@
 				aria-label={t(L.ARIA_UPLOAD_IMAGE)}
 				title={t(L.ARIA_UPLOAD_IMAGE)}
 				onclick={() => {
-					// File picker → FileReader → data URL. Hostable apps that wire
-					// `onUploadImage` on the editor will see the same path used by
-					// drag-and-drop. Here in the panel we keep the inspector self-
-					// contained and write a data URL straight to `src`; consumers
-					// that want a backend upload can intercept by replacing the
-					// inspector or pre-processing the model.
+					// File picker → FileReader → data URL (shared with the gutter
+					// inserter via `pickImageFile`). Hostable apps that wire
+					// `onUploadImage` see the same path used by drag-and-drop;
+					// here in the panel we write a data URL straight to `src` to
+					// stay self-contained. The derived alt only fills an EMPTY alt
+					// (never clobbers a user-set one).
 					const doc = typeof document !== 'undefined' ? document : null;
 					if (!doc) return;
-					const input = doc.createElement('input');
-					input.type = 'file';
-					input.accept = 'image/*';
-					input.style.display = 'none';
-					input.addEventListener('change', () => {
-						const file = input.files?.[0];
-						input.remove();
-						if (!file) return;
-						const reader = new FileReader();
-						reader.onload = () => {
-							const src = typeof reader.result === 'string' ? reader.result : '';
-							if (!src) return;
-							const altGuess = file.name.replace(/\.[^/.]+$/, '') || undefined;
-							patchBlock({
-								src,
-								...(block.alt === undefined && altGuess ? { alt: altGuess } : {})
-							});
-						};
-						reader.readAsDataURL(file);
+					pickImageFile(doc, (src, altGuess) => {
+						patchBlock({
+							src,
+							...(block.alt === undefined && altGuess ? { alt: altGuess } : {})
+						});
 					});
-					doc.body.appendChild(input);
-					input.click();
 				}}
 			>
 				{#snippet icon()}<Upload />{/snippet}

src/uix/eidos/components/words/words-image-file.ts

@@ -0,0 +1,44 @@
+/**
+ * Native image-file picker → data URL.
+ *
+ * Shared by the two Words consumers that let the user insert an image
+ * from disk: the gutter inserter (`words-block-gutter.svelte`) and the
+ * inspector's image panel upload button (`words-block-panel.svelte`).
+ * Both need the identical "open file dialog → FileReader → data URL"
+ * flow, so it lives here once instead of being copy-pasted.
+ *
+ * Kept as a plain helper (NOT routed through ActiveDom): a transient
+ * `<input type="file">` plus `FileReader` is not instrumented by the
+ * active-dom runtime, so a direct `Document` touch is correct here. The
+ * caller resolves the right `Document` (content's `ownerDocument`, or the
+ * global as a fallback) and passes it in, keeping this helper SSR-safe
+ * and portal/iframe-correct.
+ *
+ * `onPick` fires only when the user actually chooses a file; it receives
+ * the data-URL `src` and a derived `alt` (the filename without its
+ * extension, or `undefined` when the name is empty).
+ */
+export function pickImageFile(
+	doc: Document,
+	onPick: (src: string, alt: string | undefined) => void
+): void {
+	const input = doc.createElement('input');
+	input.type = 'file';
+	input.accept = 'image/*';
+	input.style.display = 'none';
+	input.addEventListener('change', () => {
+		const file = input.files?.[0];
+		input.remove();
+		if (!file) return;
+		const reader = new FileReader();
+		reader.onload = () => {
+			const src = typeof reader.result === 'string' ? reader.result : '';
+			if (!src) return;
+			const alt = file.name.replace(/\.[^/.]+$/, '') || undefined;
+			onPick(src, alt);
+		};
+		reader.readAsDataURL(file);
+	});
+	doc.body.appendChild(input);
+	input.click();
+}

src/uix/soma/components/words/engine/block-tree.ts

@@ -84,11 +84,8 @@ function childStacks(node: { type?: string; [k: string]: unknown }): ChildStack[
 	return [];
 }
 
-function kindOf(
-	stack: ChildStack,
-	child: { type?: string }
-): WordsAncestryNode['kind'] {
-	return stack.fixedKind ?? ((child.type as WordsBlock['type']) ?? 'column');
+function kindOf(stack: ChildStack, child: { type?: string }): WordsAncestryNode['kind'] {
+	return stack.fixedKind ?? (child.type as WordsBlock['type']) ?? 'column';
 }
 
 /**
@@ -101,17 +98,26 @@ export function findBlockById(doc: WordsDocument, idPath: string): WordsBlockLoc
 	const segments = idPath.split(ID_PATH_SEP).filter(Boolean);
 	if (segments.length === 0) return null;
 
-	let container: { type?: string; [k: string]: unknown } = doc as never;
-	const ancestry: WordsAncestryNode[] = [
-		{ id: null, idPath: '', kind: 'document', index: -1 }
-	];
+	// `childStacks` reads `type` + the container-specific child arrays
+	// (`children` / `columns` / `items` / `rows` / `cells`) off a permissive
+	// shape. `WordsDocument` carries `children` but no index signature, so it
+	// isn't structurally assignable — assert the descend-node shape once via
+	// `as unknown as` (the honest cast; `as never` disabled checking entirely).
+	let container: { type?: string; [k: string]: unknown } = doc as unknown as {
+		type?: string;
+		[k: string]: unknown;
+	};
+	const ancestry: WordsAncestryNode[] = [{ id: null, idPath: '', kind: 'document', index: -1 }];
 	const path: number[] = [];
 	let node: WordsBlockLocation['node'] | null = null;
 
 	for (let s = 0; s < segments.length; s++) {
 		const seg = segments[s];
-		let matched: { child: ChildStack['items'][number]; index: number; kind: WordsAncestryNode['kind'] } | null =
-			null;
+		let matched: {
+			child: ChildStack['items'][number];
+			index: number;
+			kind: WordsAncestryNode['kind'];
+		} | null = null;
 		for (const stack of childStacks(container)) {
 			const idx = stack.items.findIndex((it) => it.id === seg);
 			if (idx >= 0) {