feat(server): expose main credit stat to reflect only album artist | artist credit (#4268)

* attempt using artist | albumartist

* add primary stats, expose to ND and Subsonic

* response to feedback (1)

* address feedback part 1

* fix docs and artist show

* fix migration order

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Co-authored-by: Deluan Quintão <deluan@navidrome.org>

ui/src/artist/ArtistShow.jsx

@@ -96,10 +96,10 @@ const ArtistShowLayout = (props) => {
   let perPage = 0
   let pagination = null
 
-  const count = Math.max(
-    record?.stats?.['albumartist']?.albumCount || 0,
-    record?.stats?.['artist']?.albumCount ?? 0,
-  )
+  // Use the main credit count instead of total count, as this is a precise measure
+  // of the number of albums where the artist is credited as an album artist OR
+  // artist
+  const count = record?.stats?.['maincredit']?.albumCount || 0
 
   if (count > maxPerPage) {
     perPage = Math.trunc(maxPerPage / perPageOptions[0]) * perPageOptions[0]

ui/src/i18n/en.json

@@ -124,7 +124,8 @@
         "mixer": "Mixer |||| Mixers",
         "remixer": "Remixer |||| Remixers",
         "djmixer": "DJ Mixer |||| DJ Mixers",
-        "performer": "Performer |||| Performers"
+        "performer": "Performer |||| Performers",
+        "maincredit": "Album Artist or Artist |||| Album Artists or Artists"
       },
       "actions": {
         "topSongs": "Top Songs",