Add OG Image field to content editor (#328)

* Add OG Image field to content editor

The `_emdash_seo` table and content API already support `seo_image`, but
the admin UI had no way to set it. This adds:

- `SeoImageField` component using the existing `MediaPickerModal`
- 2-column grid layout placing the OG Image next to the Featured Image
- `description` prop on `ImageFieldRenderer` for helper text below images
- Preserve `seo.image` in `SeoPanel.emitChange` so sidebar edits don't
  clear the image

Closes #327

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* style: format

* Add changeset and fix stale seo.image in SeoPanel

- Add changeset for @emdash-cms/admin patch release
- Remove image from SeoPanel.emitChange to avoid overwriting
  a freshly-selected OG image with a stale prop value

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Address review feedback on OG Image field

- Fix #1: Use @phosphor-icons/react instead of lucide-react
- Fix #2: Send minimal patch { image } instead of spreading stale seo props
- Fix #3: Only show OG Image next to the featured_image field, not all image fields
- Fix #4: Only add description text for the featured_image field
- Fix #5: Add responsive breakpoint (grid-cols-1 md:grid-cols-2)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* style: format

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: emdashbot[bot] <emdashbot[bot]@users.noreply.github.com>
Co-authored-by: Matt Kane <mkane@cloudflare.com>

.changeset/add-og-image-field.md

@@ -0,0 +1,5 @@
+---
+"@emdash-cms/admin": patch
+---
+
+Add OG Image field to content editor

packages/admin/src/components/ContentEditor.tsx

@@ -66,6 +66,7 @@ import {
 } from "./PortableTextEditor";
 import { RevisionHistory } from "./RevisionHistory";
 import { SaveButton } from "./SaveButton";
+import { SeoImageField } from "./SeoImageField";
 import { SeoPanel } from "./SeoPanel";
 import { TaxonomySidebar } from "./TaxonomySidebar";
 
@@ -613,25 +614,46 @@ export function ContentEditor({
 						)}
 					>
 						<div className="space-y-4">
-							{Object.entries(fields).map(([name, field]) => (
-								<FieldRenderer
-									key={name}
-									name={name}
-									field={field}
-									value={formData[name]}
-									onChange={handleFieldChange}
-									onEditorReady={field.kind === "portableText" ? setPortableTextEditor : undefined}
-									minimal={isDistractionFree}
-									pluginBlocks={pluginBlocks}
-									onBlockSidebarOpen={
-										field.kind === "portableText" ? handleBlockSidebarOpen : undefined
-									}
-									onBlockSidebarClose={
-										field.kind === "portableText" ? handleBlockSidebarClose : undefined
-									}
-									manifest={manifest}
-								/>
-							))}
+							{Object.entries(fields).map(([name, field]) => {
+								const fieldEl = (
+									<FieldRenderer
+										key={name}
+										name={name}
+										field={field}
+										value={formData[name]}
+										onChange={handleFieldChange}
+										onEditorReady={
+											field.kind === "portableText" ? setPortableTextEditor : undefined
+										}
+										minimal={isDistractionFree}
+										pluginBlocks={pluginBlocks}
+										onBlockSidebarOpen={
+											field.kind === "portableText" ? handleBlockSidebarOpen : undefined
+										}
+										onBlockSidebarClose={
+											field.kind === "portableText" ? handleBlockSidebarClose : undefined
+										}
+										manifest={manifest}
+									/>
+								);
+								if (
+									name === "featured_image" &&
+									field.kind === "image" &&
+									hasSeo &&
+									!isNew &&
+									onSeoChange
+								) {
+									return (
+										<div key={`${name}-with-seo`} className="grid grid-cols-1 gap-6 md:grid-cols-2">
+											<div>{fieldEl}</div>
+											<div>
+												<SeoImageField seo={item?.seo} onChange={onSeoChange} />
+											</div>
+										</div>
+									);
+								}
+								return fieldEl;
+							})}
 						</div>
 					</div>
 				</div>
@@ -1138,6 +1160,11 @@ function FieldRenderer({
 			return (
 				<ImageFieldRenderer
 					label={label}
+					description={
+						name === "featured_image"
+							? "Used as the main visual for this post on listing pages and at the top of the post"
+							: undefined
+					}
 					value={imageValue}
 					onChange={handleChange}
 					required={field.required}
@@ -1185,12 +1212,19 @@ interface ImageFieldValue {
  */
 interface ImageFieldRendererProps {
 	label: string;
+	description?: string;
 	value: ImageFieldValue | string | undefined;
 	onChange: (value: ImageFieldValue | undefined) => void;
 	required?: boolean;
 }
 
-function ImageFieldRenderer({ label, value, onChange, required }: ImageFieldRendererProps) {
+function ImageFieldRenderer({
+	label,
+	description,
+	value,
+	onChange,
+	required,
+}: ImageFieldRendererProps) {
 	const [pickerOpen, setPickerOpen] = React.useState(false);
 	// Normalize value to get display URL (handles both object and legacy string)
 	// Prefer previewUrl for admin display, fall back to src, then derive from storageKey/id
@@ -1265,6 +1299,7 @@ function ImageFieldRenderer({ label, value, onChange, required }: ImageFieldRend
 				mimeTypeFilter="image/"
 				title={`Select ${label}`}
 			/>
+			{description && <p className="text-xs text-kumo-subtle mt-1">{description}</p>}
 			{required && !displayUrl && (
 				<p className="text-sm text-kumo-danger mt-1">This field is required</p>
 			)}

packages/admin/src/components/SeoImageField.tsx

@@ -0,0 +1,84 @@
+/**
+ * SEO OG Image field for the content editor.
+ *
+ * Renders an image picker (reusing MediaPickerModal) that stores the
+ * selected image URL in `seo.image`. Designed to sit next to the
+ * Featured Image field in a two-column grid.
+ */
+
+import { Button, Label } from "@cloudflare/kumo";
+import { Image as ImageIcon, X } from "@phosphor-icons/react";
+import * as React from "react";
+
+import type { ContentSeo, ContentSeoInput, MediaItem } from "../lib/api";
+import { MediaPickerModal } from "./MediaPickerModal";
+
+export interface SeoImageFieldProps {
+	seo?: ContentSeo;
+	onChange: (seo: ContentSeoInput) => void;
+}
+
+export function SeoImageField({ seo, onChange }: SeoImageFieldProps) {
+	const [pickerOpen, setPickerOpen] = React.useState(false);
+	const imageUrl = seo?.image || null;
+
+	const handleSelect = (item: MediaItem) => {
+		const isLocalProvider = !item.provider || item.provider === "local";
+		const url = isLocalProvider
+			? `/_emdash/api/media/file/${item.storageKey || item.id}`
+			: item.url;
+		onChange({ image: url });
+	};
+
+	const handleRemove = () => {
+		onChange({ image: null });
+	};
+
+	return (
+		<div>
+			<Label>OG Image</Label>
+			{imageUrl ? (
+				<div className="mt-2 relative group">
+					<img src={imageUrl} alt="" className="max-h-48 rounded-lg border object-cover" />
+					<div className="absolute top-2 right-2 opacity-0 group-hover:opacity-100 transition-opacity flex gap-1">
+						<Button type="button" size="sm" variant="secondary" onClick={() => setPickerOpen(true)}>
+							Change
+						</Button>
+						<Button
+							type="button"
+							shape="square"
+							variant="destructive"
+							className="h-8 w-8"
+							onClick={handleRemove}
+							aria-label="Remove image"
+						>
+							<X className="h-4 w-4" />
+						</Button>
+					</div>
+				</div>
+			) : (
+				<Button
+					type="button"
+					variant="outline"
+					className="mt-2 w-full h-32 border-dashed"
+					onClick={() => setPickerOpen(true)}
+				>
+					<div className="flex flex-col items-center gap-2 text-kumo-subtle">
+						<ImageIcon className="h-8 w-8" />
+						<span>Select OG image</span>
+					</div>
+				</Button>
+			)}
+			<p className="text-xs text-kumo-subtle mt-1">
+				Image shown when this page is shared on social media
+			</p>
+			<MediaPickerModal
+				open={pickerOpen}
+				onOpenChange={setPickerOpen}
+				onSelect={handleSelect}
+				mimeTypeFilter="image/"
+				title="Select OG Image"
+			/>
+		</div>
+	);
+}