feat: duplicates resolve themselves without Lidarr (M502 #5517)

Lidarr is off, and with it the resolver had stopped merging: it only
merged when Lidarr had said which copies it mapped. Minstrel is now the
only program writing the library, so the rule is about the copies:

- A song held twice on one album: the extra copies merge into the one
  whose tags fit best (then lossless, larger, older).
- Across releases or under another title: when every copy but one is a
  video rip (held back, or named like one and not marked fine), the rips
  merge into the one that is not.
- Clean copies on different releases are linked as one song, as before.
- Anything else waits for the operator.

Gone with Lidarr: release switches and their settle window, the
unmapped-file read, the rip search, the merge guard and its 409/503,
lidarr.Client's release methods, and duplicate_group_members.lidarr_state
(migration 0078). The duplicates page drops the per-copy Lidarr badge
and the blocked-merge notice; past release changes stay in its history.

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

web/src/routes/admin/duplicates/duplicates.test.ts

@@ -66,7 +66,6 @@ function member(id: string, extra: Partial<AdminDuplicatesResponse['groups'][num
     added_at: ago(500 * HOUR),
     like_count: 0,
     play_count: 0,
-    lidarr_state: null,
     disc_number: null,
     track_number: null,
     ...extra
@@ -332,7 +331,9 @@ describe('admin duplicates', () => {
       expect(dismissDuplicateGroup).toHaveBeenCalledWith('g-1');
     });
 
-    test('Resolved automatically lists merges and release changes', async () => {
+    // Release changes stopped with Lidarr (M502), but the ones made before stay
+    // in the history.
+    test('Resolved automatically lists merges and past release changes', async () => {
       renderWith(response(), [
         {
           id: 'a-1',
@@ -340,7 +341,7 @@ describe('admin duplicates', () => {
           created_at: ago(HOUR),
           details: {
             survivor_path: '/music/Gorillaz/Humanz (2017)/03 - Saturnz Barz.mp3',
-            survivor_reason: 'the copy Lidarr tracks',
+            survivor_reason: 'the copy that is not a video rip',
             removed: [{ track_id: 't-2', file_path: '/music/Gorillaz/Humanz (2017)/03 - Saturnz Barz (Official Video).mp3' }]
           }
         },
@@ -358,47 +359,26 @@ describe('admin duplicates', () => {
       ]);
       await fireEvent.click(screen.getByRole('tab', { name: /resolved automatically/i }));
       const items = screen.getAllByTestId('resolved-item').map(text);
-      expect(items[0]).toContain('Kept 03 - Saturnz Barz.mp3 (the copy Lidarr tracks) and removed 1 file');
+      expect(items[0]).toContain('Kept 03 - Saturnz Barz.mp3 (the copy that is not a video rip) and removed 1 file.');
       expect(items[1]).toContain('Lidarr now monitors Digital Media (40 tracks) of Humanz by Gorillaz');
       expect(screen.queryByTestId('duplicate-group')).toBeNull();
     });
   });
 
-  describe("Lidarr's view of each copy", () => {
-    function tracked() {
+  describe("the resolver's note", () => {
+    test('shows above the group it explains', () => {
       const r = response();
-      r.groups[0] = {
-        ...r.groups[0],
-        resolve_note: 'Lidarr tracks every copy as its own track.',
-        members: [member('www-01', { lidarr_state: 'tracked' }), member('www-02', { lidarr_state: 'unmapped' })]
-      };
-      return r;
-    }
-
-    test('each copy says whether Lidarr uses it, and the resolver note shows', () => {
-      renderWith(tracked());
-      expect(screen.getAllByTestId('lidarr-state').map(text)).toEqual([
-        'Lidarr uses this',
-        "Lidarr doesn't use this"
-      ]);
-      expect(text(screen.getByTestId('resolve-note'))).toBe('Lidarr tracks every copy as its own track.');
+      r.groups[0] = { ...r.groups[0], resolve_note: 'Identical audio filed under different titles.' };
+      renderWith(r);
+      expect(text(screen.getByTestId('resolve-note'))).toBe('Identical audio filed under different titles.');
     });
 
-    // Keeping the unmapped copy would remove the one Lidarr uses. The server
-    // refuses that; the confirm says so first and offers no button to press.
-    test('a merge that would remove the copy Lidarr uses is blocked before it is sent', async () => {
-      renderWith(tracked());
+    test('a merge confirms and sends the copy chosen to keep', async () => {
+      renderWith(response());
       await fireEvent.click(screen.getAllByRole('radio')[1]);
       await fireEvent.click(screen.getByRole('button', { name: 'Merge…' }));
-      expect(text(screen.getByTestId('merge-blocked'))).toContain('Lidarr uses a copy this would remove');
-      const confirm = screen.getByRole('button', { name: 'Remove 1 file and merge' }) as HTMLButtonElement;
-      expect(confirm.disabled).toBe(true);
-
-      // Choosing the copy Lidarr uses clears it.
-      await fireEvent.click(screen.getAllByRole('radio')[0]);
-      expect(screen.queryByTestId('merge-blocked')).toBeNull();
       await fireEvent.click(screen.getByRole('button', { name: 'Remove 1 file and merge' }));
-      expect(mergeDuplicateGroup).toHaveBeenCalledWith('g-1', { survivor_track_id: 'www-01', unmonitor: false });
+      expect(mergeDuplicateGroup).toHaveBeenCalledWith('g-1', { survivor_track_id: 'www-02', unmonitor: false });
     });
   });
 });