Emdash source with visual editor image upload fix

Fixes:
1. media.ts: wrap placeholder generation in try-catch
2. toolbar.ts: check r.ok, display error message in popover

packages/admin/src/components/EditorHeader.tsx

@@ -0,0 +1,93 @@
+/**
+ * EditorHeader
+ *
+ * Shared sticky header used by editor pages (Content, Content Type, Section,
+ * Settings) so the primary save action is always visible at the top of the
+ * page while users scroll through long forms.
+ *
+ * Why sticky:
+ *   The main content area in `Shell` (`<main className="overflow-y-auto">`)
+ *   is the scroll container. `position: sticky; top: 0` pins this header to
+ *   the top of that container so the Save button stays in view.
+ *
+ * Accessibility:
+ *   The sticky header is the *primary* save affordance for sighted/pointer
+ *   users, but it doesn't replace a save action at the natural end of the
+ *   form. Editor pages that use this header continue to render their existing
+ *   bottom-of-form save button so keyboard and screen-reader users hit it as
+ *   the last interactive control on the page (DOM order matches logical order).
+ *
+ * RTL:
+ *   Avoids physical left/right Tailwind utilities. The component itself uses
+ *   only symmetric horizontal utilities (`-mx-*`, `px-*`), which are
+ *   direction-agnostic. Callers passing directional content into the
+ *   `leading` / `actions` slots should use logical classes (`ms-*`, `me-*`,
+ *   `start-*`, `end-*`) for any side-specific spacing or positioning.
+ */
+
+import * as React from "react";
+
+import { cn } from "../lib/utils";
+
+export interface EditorHeaderProps {
+	/** Optional leading element, typically a back-link or close button. */
+	leading?: React.ReactNode;
+	/** Header title content. Pass a heading element so semantics are correct. */
+	children: React.ReactNode;
+	/** Right-aligned action area (Save, Publish, etc.). */
+	actions?: React.ReactNode;
+	/**
+	 * When `true`, the header sticks to the top of its scroll container.
+	 * Defaults to `true`. Set to `false` to render a static header (e.g. when
+	 * the parent wants to control positioning, or when the page itself is in
+	 * a special mode like distraction-free).
+	 */
+	sticky?: boolean;
+	className?: string;
+}
+
+/**
+ * Sticky editor header with consistent placement of save / primary actions.
+ *
+ * Usage:
+ *
+ *   <EditorHeader
+ *       leading={<BackLink />}
+ *       actions={<SaveButton ... />}
+ *   >
+ *       <h1 className="text-2xl font-bold">{title}</h1>
+ *   </EditorHeader>
+ */
+export function EditorHeader({
+	leading,
+	children,
+	actions,
+	sticky = true,
+	className,
+}: EditorHeaderProps) {
+	return (
+		<div
+			data-editor-header
+			className={cn(
+				// Negative inline margins + padding cancel out the parent <main>'s
+				// p-6 so the header background spans edge-to-edge of the scroll
+				// container while still aligning content to the original gutter.
+				sticky && "sticky top-0 z-30 -mx-6 -mt-6 px-6 pt-6",
+				// Solid background so content scrolling behind doesn't bleed through.
+				sticky && "bg-kumo-base/95 supports-[backdrop-filter]:bg-kumo-base/80 backdrop-blur",
+				// Subtle separator + bottom padding so it visually detaches from form.
+				sticky && "pb-3 mb-3 border-b border-kumo-line",
+				"flex flex-wrap items-center justify-between gap-y-2 gap-x-4",
+				className,
+			)}
+		>
+			<div className="flex items-center gap-4 min-w-0">
+				{leading}
+				<div className="min-w-0">{children}</div>
+			</div>
+			{actions && <div className="flex items-center gap-2 flex-wrap">{actions}</div>}
+		</div>
+	);
+}
+
+export default EditorHeader;