feat: add permanent deletion for revoked keys

DELETE /admin/api/keys/{id}/purge removes the key record; it requires the key to be revoked first and keeps historical logs. The keys page swaps the revoke button for a delete button once a key is revoked.

internal/server/admin.go

@@ -203,6 +203,27 @@ func (s *Server) keys(w http.ResponseWriter, r *http.Request) {
 }
 func (s *Server) keyID(w http.ResponseWriter, r *http.Request) {
 	id := strings.TrimPrefix(r.URL.Path, "/admin/api/keys/")
+	if purgeID, ok := strings.CutSuffix(id, "/purge"); ok {
+		if r.Method != "DELETE" {
+			errJSON(w, 405, "method not allowed")
+			return
+		}
+		var revoked bool
+		if e := s.db.QueryRow("SELECT revoked FROM keys WHERE id=?", purgeID).Scan(&revoked); e == sql.ErrNoRows {
+			errJSON(w, 404, "not found")
+			return
+		} else if e != nil {
+			errJSON(w, 500, "database error")
+			return
+		}
+		if !revoked {
+			errJSON(w, 409, "revoke the key before deleting")
+			return
+		}
+		res, e := s.db.Exec("DELETE FROM keys WHERE id=?", purgeID)
+		mutation(w, res, e)
+		return
+	}
 	if r.Method == "DELETE" {
 		res, e := s.db.Exec("UPDATE keys SET enabled=0,revoked=1 WHERE id=?", id)
 		mutation(w, res, e)