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/reacquisition/sweeper_test.go

@@ -15,6 +15,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/dbtest"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrconfig"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrrequests"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/notifications"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/tags"
 )
 
@@ -84,9 +85,10 @@ func TestSweep_RequestsAlbumsByReleaseGroup_Integration(t *testing.T) {
 	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
 	q := dbq.New(pool)
 
-	if _, err := q.CreateUser(ctx, dbq.CreateUserParams{
+	admin, err := q.CreateUser(ctx, dbq.CreateUserParams{
 		Username: dbtest.TestUserPrefix + "sweepadmin", PasswordHash: "x", ApiTokenHash: "x", IsAdmin: true,
-	}); err != nil {
+	})
+	if err != nil {
 		t.Fatal(err)
 	}
 	settings, err := NewSettingsService(ctx, pool, logger)
@@ -105,6 +107,7 @@ func TestSweep_RequestsAlbumsByReleaseGroup_Integration(t *testing.T) {
 
 	requests := lidarrrequests.NewService(pool, lidarrconfig.New(pool), nil, nil)
 	s := NewSweeper(pool, settings, requests, logger)
+	s.SetNotifier(notifications.New(pool, nil, nil))
 	asked := map[string]int{}
 	s.releaseGroup = func(_ context.Context, release string) (string, error) {
 		asked[release]++
@@ -153,6 +156,20 @@ SELECT lr.lidarr_album_mbid
 	if attempts != 0 {
 		t.Errorf("unresolvable album spent an attempt (%d state rows)", attempts)
 	}
+	// M489: the two requests filed without auto-approval wait on an admin,
+	// so each reaches the admins' inbox; the unresolvable album filed none.
+	inbox, err := q.ListNotifications(ctx, dbq.ListNotificationsParams{UserID: admin.ID, PageLimit: 10})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(inbox) != 2 {
+		t.Errorf("admin inbox holds %d notifications, want 2", len(inbox))
+	}
+	for _, n := range inbox {
+		if n.Kind != string(notifications.KindRequestPending) {
+			t.Errorf("admin inbox holds %q, want request_pending", n.Kind)
+		}
+	}
 	var stray int
 	if err := pool.QueryRow(ctx, "SELECT count(*) FROM lidarr_requests WHERE lidarr_album_mbid LIKE 'release-%'").Scan(&stray); err != nil {
 		t.Fatal(err)