feat(notifications): requests and flags reach the people who act on them (#5340)

- A new request still pending after any auto-approval notifies the
  admins (request_pending), but not the requester if they are an admin.
  A request that dedups into one already in flight is not announced again.
- Approving or rejecting a request notifies the requester, and a
  rejection carries the admin's notes as the reason. An admin deciding
  their own request gets nothing.
- The reconciler notifies the requester when their request arrives
  (request_completed), linking the matched album or artist.
- A request the re-acquisition sweeper files and cannot approve itself
  notifies the admins.
- A quarantine flag notifies every admin except the flagger, naming the
  track, the flagger and the reason.

lidarrrequests.Service.CreateTracked reports whether a request was
inserted or deduped; Create wraps it.

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

internal/lidarrrequests/reconciler_notify_test.go

@@ -0,0 +1,52 @@
+package lidarrrequests
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrconfig"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/notifications"
+)
+
+// M489: an album request that arrives lands in the requester's inbox once,
+// linked to the album it matched.
+func TestReconciler_CompletionNotifiesRequester(t *testing.T) {
+	pool := newPool(t)
+	q := dbq.New(pool)
+	ctx := context.Background()
+
+	enableLidarrForPool(t, pool)
+	user := seedUser(t, pool)
+	artist := seedArtist(t, q, "Notify Artist", "notify-artist-mbid")
+	album := seedAlbum(t, q, artist.ID, "Notify Album", "notify-album-mbid")
+	_ = seedTrack(t, q, album.ID, artist.ID, "Notify Track", "/music/notify/01.flac")
+	seedApprovedRequestDirect(t, q, user, CreateParams{
+		Kind: "album", LidarrArtistMBID: "notify-artist-mbid", LidarrAlbumMBID: "notify-album-mbid",
+		ArtistName: "Notify Artist", AlbumTitle: "Notify Album",
+	})
+
+	rec := NewReconciler(pool, lidarrconfig.New(pool), nil, newTestLogger(), nil)
+	rec.SetNotifier(notifications.New(pool, nil, nil))
+	for i := 0; i < 2; i++ { // the second tick finds nothing left to complete
+		if err := rec.tickOnce(ctx); err != nil {
+			t.Fatalf("tickOnce: %v", err)
+		}
+	}
+
+	rows, err := q.ListNotifications(ctx, dbq.ListNotificationsParams{UserID: user, PageLimit: 10})
+	if err != nil {
+		t.Fatalf("list notifications: %v", err)
+	}
+	if len(rows) != 1 || rows[0].Kind != string(notifications.KindRequestCompleted) {
+		t.Fatalf("inbox = %+v, want one request_completed", rows)
+	}
+	var p notifications.Payload
+	if err := json.Unmarshal(rows[0].Payload, &p); err != nil {
+		t.Fatal(err)
+	}
+	if p.Name != "Notify Artist – Notify Album" || p.AlbumID != formatUUIDForBus(album.ID) || p.ArtistID != "" {
+		t.Errorf("payload = %+v", p)
+	}
+}