feat(editor): paste and drop images into Markdown files (#489)

Pasting or dropping an image into a Markdown editor saves it beside the document in `assets/` and inserts a URL-encoded relative link as one undo step, in local and remote projects. Existing names get numbered suffixes; the folder and clipboard name pattern are in Settings › Editor › General. Non-Markdown editors, text paste and other dropped files keep their behavior.

Fixes #308

src/bindings.ts

@@ -151,6 +151,7 @@ export const commands = {
 	 *  `charset` (writes the BOM for `utf-8-bom` / UTF-16).
 	 */
 	fsCreateFile: (path: string) => typedError<null, IdeError>(__TAURI_INVOKE("fs_create_file", { path })),
+	fsCreateFileBytes: (path: string, data: number[]) => typedError<null, IdeError>(__TAURI_INVOKE("fs_create_file_bytes", { path, data })),
 	fsCreateDir: (path: string) => typedError<null, IdeError>(__TAURI_INVOKE("fs_create_dir", { path })),
 	fsRename: (from: string, to: string) => typedError<null, IdeError>(__TAURI_INVOKE("fs_rename", { from, to })),
 	/**
@@ -2700,6 +2701,8 @@ export type EditorConfigProps = {
 export type EditorGeneralSettings = {
 	/**  Change font size with ⌘ + mouse wheel. */
 	wheelZoom?: boolean,
+	markdownImageFolder?: string,
+	markdownImageNamePattern?: string,
 	/**  Drag-and-drop of selected text inside the editor. */
 	dragAndDrop?: boolean,
 	/**  When the caret moves out of view: `minimize` scrolling | `center` the caret line. */