fix(scanner): play disc-folder audiobook tracks disc by disc

The walker sorted a book's files by file name, so tracks in disc folders that reuse names, such as
CD 1/01.mp3 and CD 2/01.mp3, interleaved in playback, merged chapters, and written track numbers.
Order them by their whole path instead, everywhere a track order is chosen.

A rescan that only reorders a book's existing tracks now moves every audio bookmark and the
listening progress percentage to the same moment of the same track, and rebuilds merged chapters.
Disc folders are never skipped by incremental scans, so existing libraries are fixed by their next
scan.

Also inventory the notebook and dashboard highlights routes in the authorization matrix, and pin the
app locale in two date tests that depended on the machine's locale.

server/test/e2e/authorization-matrix/route-inventory/manifest.json

@@ -1,7 +1,7 @@
 {
-  "totalRoutes": 623,
+  "totalRoutes": 630,
   "byPermission": {
-    "(none)": 271,
+    "(none)": 278,
     "Permission.ManageMetadataConfig": 34,
     "Permission.EmailSend": 30,
     "Permission.LibraryEditMetadata": 35,