refactor(server): final writeErr migration + ErrNotFound aliases (T3c)

internal/lidarrrequests/service.go

@@ -13,6 +13,7 @@ import (
 	"github.com/jackc/pgx/v5/pgtype"
 	"github.com/jackc/pgx/v5/pgxpool"
 
+	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarr"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrconfig"
@@ -22,8 +23,11 @@ import (
 var (
 	ErrInvalidKindFields = errors.New("lidarrrequests: missing required fields for kind")
 	ErrNotPending        = errors.New("lidarrrequests: request is not pending")
-	ErrNotFound          = errors.New("lidarrrequests: request not found")
-	ErrLidarrDisabled    = errors.New("lidarrrequests: lidarr not configured")
+	// ErrNotFound aliases apierror.ErrNotFound so handlers can errors.Is
+	// against the shared sentinel; existing lidarrrequests.ErrNotFound
+	// callsites still resolve to the same pointer.
+	ErrNotFound       = apierror.ErrNotFound
+	ErrLidarrDisabled = errors.New("lidarrrequests: lidarr not configured")
 	// ErrDefaultsIncomplete fires when Lidarr is enabled but the operator
 	// hasn't picked a default quality profile or root folder. Without those,
 	// Lidarr's add-artist/add-album endpoints reject the payload with a