AssetPicker 7/7: Wire AssetPicker into Edit Content File/Image fields

[nicobytes]

Description

Wire Edit Content File and Image fields to open DotAssetPicker instead of DotBrowserSelector, passing contentlet language and the correct mode.

Related epic: #36702
Series: AssetPicker 7/7 (final integration)

Current: dot-file-field opens DotBrowserSelectorComponent via PrimeNG DialogService with /api/v1/browser params (mimeTypes: ['image'] for Image, [] for File).

Target: Open AssetPicker with File/Image entry config from 6/7; browse via /api/v1/drive/search.

Out of scope for this issue:

• Block editor / edit-content-bridge consumers of DotBrowserSelector (keep using browser selector)
• Binary field (no existing-file picker)
• Tracked GitHub sub-issues under the epic

Acceptance Criteria

• File field “Select existing” opens AssetPicker in file mode with the contentlet language
• Image field “Select existing” opens AssetPicker in image mode with the contentlet language
• Selecting an asset sets the field preview/value the same way as today’s browser selector close contract
• Cancel leaves the field unchanged
• DotBrowserSelector remains for non-File/Image consumers (block editor, bridges)
• File-field unit tests updated/passing for the new dialog open path
• Manual check: File + Image flows match epic ACs (locale, filters, upload, last path, no folders in right pane, silent mime for Image)

Priority

Medium

Additional Context

Closes the File/Image selection path for epic #36702. Design reference and full epic ACs live on #36702.