fix(server/m7-scan-progress): forward-fix CI — ScanTrigger interface

B-T2 changed Scanner.Scan to take a progressCb parameter, but the
ScanTrigger interface in internal/server/server.go was missed. The
interface gains the same progressCb arg; the HTTP handler at
handleAdminScan passes nil (fire-and-forget triggers don't observe
partial tallies). The stubScanner in server_test.go gets the new
arg too.

internal/server/server.go

@@ -52,9 +52,11 @@ func (a lidarrUnmonitorAdapter) UnmonitorTrack(ctx context.Context, trackMbid, a
 }
 
 // ScanTrigger is the subset of the scanner the HTTP handler needs. Kept as an
-// interface so tests can stub it without touching the DB.
+// interface so tests can stub it without touching the DB. The progressCb
+// parameter (added in m7-scan-progress) lets the orchestrator drive partial-
+// tally writes; the HTTP handler passes nil for fire-and-forget triggers.
 type ScanTrigger interface {
-	Scan(ctx context.Context) (library.Stats, error)
+	Scan(ctx context.Context, progressCb func(library.Stats)) (library.Stats, error)
 }
 
 type Server struct {
@@ -151,7 +153,7 @@ func (s *Server) handleHealthz(w http.ResponseWriter, _ *http.Request) {
 // Kept synchronous for v1: libraries are small and the operator can tell when
 // it's done. Async jobs with status polling are a later-milestone concern.
 func (s *Server) handleAdminScan(w http.ResponseWriter, r *http.Request) {
-	stats, err := s.Scanner.Scan(r.Context())
+	stats, err := s.Scanner.Scan(r.Context(), nil)
 	w.Header().Set("Content-Type", "application/json")
 	if err != nil {
 		s.Logger.Error("admin scan failed", "err", err)