1. note_intention: Delete old file only when a genuinely new upload arrives
(32-char hex file_id), not when the FilePond pool preserves an existing
file by sending its DB integer ID. Previously the DB integer ID
triggered $hasNewNote=true, which deleted the existing note_intention
from disk+DB, then handleFilePondSingleFile couldn't re-process it
because the regex requires a hex pattern. Same fix applied to cover.
2. All file deletions now use deleteThesisFileToTrash() which renames
files to tmp/_trash/ instead of unlinking. The trash preserves
original filenames prefixed with DB id for traceability. Skips
website URLs and PeerTube refs (no disk file).
3. Storage prefix changed from theses/ to documents/ to reflect that
the folder holds all document types (determined by file_type in DB).
MediaController visibility gate supports both prefixes for backward
compat with existing files.
4. File browser + relink feature for orphaned files:
- /admin/fragments/file-browser.php — HTMX tree browser for
storage/documents/ and storage/theses/
- /admin/actions/filepond/relink.php — POST endpoint that inserts
a thesis_files row pointing to existing on-disk file
- Per-pool "📂 Relier" buttons (edit mode only)
- JS: XamxamOpenFileBrowser / XamxamRelinkFile with FilePond integration
- CSS: .relink-modal dialog + .file-browser tree styles
