Add image upload to Markdown editor: paste, drag-drop, toolbar button

- /api/upload-image endpoint saves images and returns URL
- Paste images from clipboard directly into the editor
- Drag and drop images onto the editor
- Toolbar image button opens file picker for manual upload
- Uploaded images inserted as ![alt](url) Markdown at cursor position

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

src/lib/components/ui/MarkdownEditor.svelte

@@ -13,6 +13,37 @@
 	let textareaEl: HTMLTextAreaElement;
 	let editor: any = null;
 
+	async function uploadImage(file: File): Promise<string | null> {
+		const formData = new FormData();
+		formData.append('file', file);
+
+		try {
+			const res = await fetch('/api/upload-image', { method: 'POST', body: formData });
+			if (!res.ok) throw new Error('Upload failed');
+			const { url } = await res.json();
+			return url;
+		} catch {
+			alert('Image upload failed');
+			return null;
+		}
+	}
+
+	function insertImageAtCursor(url: string, altText: string) {
+		if (!editor) return;
+		const cm = editor.codemirror;
+		const pos = cm.getCursor();
+		cm.replaceRange(`![${altText}](${url})\n`, pos);
+		value = editor.value();
+	}
+
+	async function handleFiles(files: FileList | File[]) {
+		for (const file of files) {
+			if (!file.type.startsWith('image/')) continue;
+			const url = await uploadImage(file);
+			if (url) insertImageAtCursor(url, file.name.replace(/\.[^.]+$/, ''));
+		}
+	}
+
 	onMount(async () => {
 		if (!browser) return;
 
@@ -25,12 +56,28 @@
 			spellChecker: false,
 			autofocus: false,
 			placeholder,
-			status: false,
+			status: ['upload'],
 			minHeight: '300px',
 			toolbar: [
 				'bold', 'italic', 'heading', '|',
 				'quote', 'unordered-list', 'ordered-list', '|',
-				'link', 'image', 'table', 'code', '|',
+				'link',
+				{
+					name: 'upload-image',
+					action: () => {
+						const input = document.createElement('input');
+						input.type = 'file';
+						input.accept = 'image/*';
+						input.multiple = true;
+						input.onchange = () => {
+							if (input.files) handleFiles(input.files);
+						};
+						input.click();
+					},
+					className: 'fa fa-image',
+					title: 'Upload Image'
+				},
+				'table', 'code', '|',
 				'preview', 'side-by-side', 'fullscreen', '|',
 				'guide'
 			],
@@ -40,6 +87,32 @@
 		editor.codemirror.on('change', () => {
 			value = editor.value();
 		});
+
+		// Drag and drop images
+		const cm = editor.codemirror;
+		cm.on('drop', (_: any, e: DragEvent) => {
+			if (e.dataTransfer?.files?.length) {
+				e.preventDefault();
+				handleFiles(e.dataTransfer.files);
+			}
+		});
+
+		// Paste images
+		cm.on('paste', (_: any, e: ClipboardEvent) => {
+			const items = e.clipboardData?.items;
+			if (!items) return;
+			const imageFiles: File[] = [];
+			for (const item of items) {
+				if (item.type.startsWith('image/')) {
+					const file = item.getAsFile();
+					if (file) imageFiles.push(file);
+				}
+			}
+			if (imageFiles.length > 0) {
+				e.preventDefault();
+				handleFiles(imageFiles);
+			}
+		});
 	});
 
 	onDestroy(() => {
@@ -80,6 +153,9 @@
 	.markdown-editor :global(.editor-toolbar button.active) {
 		background: #e5e7eb;
 	}
+	.markdown-editor :global(.editor-statusbar) {
+		display: none;
+	}
 	/* Dark mode */
 	:global(.dark) .markdown-editor :global(.CodeMirror) {
 		background: #374151;