fix(app): paste clipboard images on mobile (#2793)

Native composers had no path from the device clipboard into image attachments. Route clipboard data URLs through the existing attachment persistence flow and expose the action only in the native attachment sheet.

packages/app/src/hooks/image-attachment-picker.ts

@@ -4,7 +4,10 @@ import { getFileNameFromPath } from "@/attachments/utils";
 import { i18n } from "@/i18n/i18next";
 import { isAbsolutePath } from "@/utils/path";
 
-export type PickedImageSource = { kind: "file_uri"; uri: string } | { kind: "blob"; blob: Blob };
+export type PickedImageSource =
+  | { kind: "file_uri"; uri: string }
+  | { kind: "blob"; blob: Blob }
+  | { kind: "data_url"; dataUrl: string };
 
 export interface PickedImageAttachmentInput {
   source: PickedImageSource;