feat: implement resumable chunked media upload with progress indicators in admin UI

CHANGELOG.md

@@ -12,6 +12,7 @@
 - Extended admin schedule and dashboard data endpoints with media duration totals, runtime strings, and media counts.
 - Added admin UI runtime display for schedule/dashboard plus media library edit/delete actions.
 - Added a dedicated plain TypeScript admin module for tab navigation, media CRUD actions, schedule/system analytics refresh, and moderation workflows without Alpine dependencies.
+- Added resumable chunked admin media upload flow with upload-session endpoints and client progress indicators.
 
 ### Changed
 
@@ -27,6 +28,7 @@
 - Implemented media upload duration probing with ffprobe and persisted media metadata to the database alongside filesystem storage.
 - Updated media listing to read from the media table and return duration metadata with HH:MM:SS runtime formatting.
 - Removed Tailwind and Alpine runtime/build dependencies from the frontend package configuration and eliminated Tailwind directives/warnings during production build.
+- Enforced 2GB upload ceiling plus server-side media file type/size validation for admin uploads.
 
 ## [1.0.3] - 2026-08-03