[IMAGE EDITOR] Wire image editor Save, Download, and Cancel to FileFieldStore temp-file flow

[nicobytes]

Description

Complete the save/cancel/download flow from the Angular image editor back to the unified file field:

• Save → POST /api/v1/image/edit → DotCMSTempFile → launcher onClose → FileFieldStore.setPreviewFile
• Download → preview URL + force_download=true
• Cancel → close modal, no temp file

Field availability (Image always, Binary only when metadata.isImage, File never) is covered by #36058.

Acceptance Criteria

• Save calls REST endpoint with current filter chain + focal point; closes modal with temp file.
• Field value updated to temp file id; preview refreshes in file-field component.
• Download opens filtered URL with force_download=true in new tab.
• Cancel closes modal and emits null — field value unchanged.
• Enterprise license gate respected (match Dojo behavior).

Priority

High

Additional Context

• Epic: Edit Content Screen — GTM #35846
• Depends on: [IMAGE EDITOR] Add REST endpoint POST /api/v1/image/edit for edited image save #36061 (REST), [IMAGE EDITOR] Implement AngularImageEditorLauncher full-screen modal for new edit content #36062 (launcher), [IMAGE EDITOR] Add gated 'Edit image' action backed by IMAGE_EDITOR_LAUNCHER #36058 (edit action + availability)
• Never overwrite source binary — temp-only until workflow check-in