fix: sync-music: ensure output file names are valid on Android

sync-music/sync-music.lisp

@@ -84,10 +84,12 @@ Return the action if it exists, or NIL if the file should not be copied."
                                      data-raw)
             :for metadata-filtered := (delete-if (compose #'emptyp #'cdr) metadata)
             :for previous-action := nil :then current-action
-            :for output-file-name := (substitute #\! #\/ (format nil
+            :for output-file-name := (ppcre:regex-replace-all *invalid-char-scanner*
+                                                              (format nil
                                                                       "~A - ~A"
                                                                       track-number
-                                                                 track-title))
+                                                                      track-title)
+                                                              "!!!")
             :for current-action := (make-copy-flac-action
                                     :origin origin-file
                                     :target (pathname-normalize-unicode

sync-music/utils.lisp

@@ -21,6 +21,9 @@
 (defparameter *timestamp-scanner* (ppcre:create-scanner "^(\\d+):(\\d{2})\\.(\\d{2})$")
   "Scan for a cuetools position.")
 
+(defparameter *invalid-char-scanner* (ppcre:create-scanner "[\"*/:<>?\\\\|]")
+  "Scan for any characters not allowed in an Android/NTFS file name.")
+
 (defun maybe-normalize-unicode (s)
   (if (stringp s) (uax-15:normalize s :nfc) s))