fix(launcher): resolve 'download' filename bug and refactor data_url to global page state

- Updated 'handle_open_file' in launcher_file_cont.svelte to correctly pass filename to API.
- Fixed WebSocket ae_download command in launcher layout to include filename.
- Implemented a safety net in api_get_object.ts to extract filename from params if missing.
- Added 'download' attribute to Hosted Files download button for direct links.
- Refactored launcher menu components to use Svelte 5 global 'page' state instead of obsolete 'data_url' prop.

src/lib/ae_core/ae_comp__hosted_files_download_button.svelte

@@ -280,6 +280,7 @@
     {#if show_direct_download}
         <a
             href={direct_download_url}
+            download={ae_util.clean_filename(final_filename)}
             class={variant_classes}
             title={`Direct download (V3 Action):\n${final_filename}\n[API] SHA256: ${hosted_file_obj?.hash_sha256?.slice(0, 10)}...\nHosted ID: ${file_id}`}
         >