feat(workspace): bring an extracted note back into the bullet

A bullet that is only a link to a note (as left by /extract) gets a
"Notiz zurückholen" button. POST /documents/{id}/inline returns the
linked note's blocks with fresh ids and trashes the note; the editor
puts the title back as text and inserts the blocks as an own edit, so
Strg+Z restores the link and the note. Only own notes that no other
note links to. Release 0.52.0.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/api/server.go

@@ -173,6 +173,7 @@ func (s *Server) Router() http.Handler {
 		r.Post("/api/v1/tasks/{id}/watch", s.handleWatchTask)
 		r.Delete("/api/v1/tasks/{id}/watch", s.handleWatchTask)
 		r.Post("/api/v1/documents/{id}/extract/undo", s.handleUndoExtract)
+		r.Post("/api/v1/documents/{id}/inline", s.handleInlineNote)
 		r.Post("/api/v1/documents/{id}/merge", s.handleMergeDocuments)
 		r.Post("/api/v1/documents/{id}/merge/undo", s.handleUndoMerge)
 		r.Get("/api/v1/link-preview", s.notInDemo(s.handleLinkPreview))