fix: disable Milkdown ImageBlock so paste never strands an upload node

Routing pasted images to the attachment strip wasn't enough — the editor's
ImageBlock feature still handled the paste itself and left a stuck "upload
in progress" node, since there's no public upload URL for it to resolve to.

Turn the feature off entirely. It's the root cause: it's the only thing
that registers paste/drop-to-upload. Image *links* still render through the
base commonmark schema (a plain <img>), and pasted image files continue to
go to the attachment strip via use-file-input. Drop the now-dead image-block
upload/chrome CSS and keep a simple inline-image style.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QtNQeBpkDJPC9obiB25pV6

js/desktop/src/features/compose/markdown-editor.css

@@ -110,26 +110,12 @@
   margin-top: 0;
 }
 
-/* Images come from URLs only (no stable public upload URL), so hide the
- * file uploader — the placeholder then just prompts for a link. */
-.llink-crepe
-  .milkdown
-  :is(.milkdown-image-block, .milkdown-image-inline)
-  .placeholder
-  .uploader {
-  display: none;
-}
-
-/* Read-only renders the image node view with inert editing chrome — hide it. */
-.llink-crepe:not(.llink-crepe--fill) .milkdown .milkdown-image-block .operation,
-.llink-crepe:not(.llink-crepe--fill)
-  .milkdown
-  .milkdown-image-block
-  .image-resize-handle {
-  display: none;
-}
-
-.llink-crepe .milkdown .milkdown-image-block img {
+/* Image *links* render through the base commonmark schema (the ImageBlock
+ * feature is off — see markdown-editor.tsx). Keep them within the content
+ * column and softly rounded. */
+.llink-crepe .milkdown .ProseMirror img {
+  max-width: 100%;
+  max-height: 420px;
   border-radius: 8px;
 }
 

js/desktop/src/features/compose/markdown-editor.tsx

@@ -57,23 +57,18 @@ export function MarkdownEditor({
         [Crepe.Feature.BlockEdit]: !readOnly,
         [Crepe.Feature.Toolbar]: !readOnly,
         [Crepe.Feature.Placeholder]: !readOnly,
-        [Crepe.Feature.ImageBlock]: true,
+        // Off on purpose: file uploads aren't supported, so this feature's
+        // paste/drop handler would only strand an "upload in progress" node in
+        // the editor. Image *links* still render through the base commonmark
+        // schema, and pasted image files are routed to the compose attachment
+        // strip (see use-file-input).
+        [Crepe.Feature.ImageBlock]: false,
         [Crepe.Feature.Latex]: false,
         [Crepe.Feature.TopBar]: false,
         [Crepe.Feature.AI]: false,
       },
       featureConfigs: {
         [Crepe.Feature.Placeholder]: { text: placeholder ?? '' },
-        // Images come from URLs only (e.g. pasted markdown) — there is no
-        // stable public upload URL, so the file uploader is hidden in CSS and
-        // onUpload rejects in case a file ever reaches it anyway (the default
-        // would serialize an ephemeral blob: URL into the message).
-        [Crepe.Feature.ImageBlock]: {
-          blockUploadPlaceholderText: 'Paste an image link…',
-          inlineUploadPlaceholderText: 'paste an image link',
-          maxHeight: 420,
-          onUpload: () => Promise.reject(new Error('Image uploads disabled')),
-        },
       },
     });