feat(hosted-files): introduce standardized download component and V3 action support

- Created AE_Comp_Hosted_Files_Download_Button using Svelte 5 and Lucide icons.
- Added file_extension_icon_lucide utility for direct Lucide icon mapping.
- Refactored download logic to core__hosted_files.ts using V3 Action endpoint (/v3/action/hosted_file/.../download).
- Integrated new component into Event File Object Table.
- Cleaned up legacy window.postMessage calls in several file management views.

NOTE: The new download component is currently in development and may not be fully functional.

src/lib/elements/element_manage_event_file_li.svelte

@@ -183,7 +183,6 @@
                                                     log_lvl: 0
                                                 });
 
-                                            // window.postMessage({ type: 'download_event_file', event_file_id: event_file_obj.event_file_id, filename: event_file_obj.filename, auto_download: true }, '*');
                                         }}
                                         class="btn btn-sm lg:btn-md preset-tonal-primary hover:preset-filled-primary-500 min-w-72 lg:min-w-96"
                                         title={`Download this file:\n${event_file_obj.filename}\n[API] SHA256: ${event_file_obj.hash_sha256.slice(0, 10)}... Hosted ID: ${event_file_obj.hosted_file_id} Event File ID: ${event_file_obj.event_file_id}`}