[6.x] Add chunked asset uploads and direct S3 multipart uploads

CHANGELOG.md

@@ -7,6 +7,11 @@
 
 - Moved legacy relation-field settings HTML and entry-title input HTML into the Yii adapter. ([#19591](https://github.com/craftcms/cms/pull/19591))
 - Migrated the reassign entries, replace relations, and replace references modals to the Form API. ([#19589](https://github.com/craftcms/cms/pull/19589))
+- Added shared upload sessions for assets and user photos, direct S3 multipart uploads, upload retry and cancellation controls, and extensible upload transports and destination handlers.
+- Added background uploads in the Assets index that continue during Control Panel navigation, with persistent progress, retry, cancellation, and filename-conflict controls.
+- Changed `users/upload-user-photo` to start an upload session using JSON file metadata instead of multipart file data.
+- Fixed user photo asset selections not being saved, and restricted the photo selector to images in the configured volume and subfolder.
+- Removed the `assets/upload` and `assets/replace-file` multipart endpoints. Asset uploads now use upload sessions, and filename conflicts are resolved through `assets/resolve-upload-conflict`.
 - Added support for refreshable standard plugin settings forms and conditional configuration of core form nodes. ([#19545](https://github.com/craftcms/cms/pull/19545))
 - Added support for sending queued Laravel notifications to `CraftCms\Cms\User\Elements\User` elements. ([#19541](https://github.com/craftcms/cms/pull/19541))
 - Added Markdown comments to element activity timelines, with support for editing, removing, structured user mentions, and email notifications.

composer.json

@@ -87,6 +87,7 @@
     "laravel/pao": "^1.0",
     "laravel/pint": "^1.22",
     "laravel/socialite": "^5.23",
+    "league/flysystem-aws-s3-v3": "^3.35",
     "orchestra/testbench": "^11.0",
     "pestphp/pest": "^5.0",
     "pestphp/pest-plugin-agent": "^5.0",