feat(server): mount /api/* (login, logout, me)

Wires the native JSON surface alongside the existing /api/admin
and /rest/* routes. Subsonic compatibility remains untouched.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/server/server.go

@@ -10,6 +10,7 @@ import (
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/jackc/pgx/v5/pgxpool"
 
+	"git.fabledsword.com/bvandeusen/minstrel/internal/api"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/subsonic"
@@ -40,13 +41,12 @@ func (s *Server) Router() http.Handler {
 	r.Get("/healthz", s.handleHealthz)
 
 	if s.Pool != nil {
-		r.Route("/api", func(api chi.Router) {
-			api.Route("/admin", func(admin chi.Router) {
-				admin.Use(auth.RequireAdmin(s.Pool))
-				if s.Scanner != nil {
-					admin.Post("/scan", s.handleAdminScan)
-				}
-			})
+		api.Mount(r, s.Pool, s.Logger)
+		r.Route("/api/admin", func(admin chi.Router) {
+			admin.Use(auth.RequireAdmin(s.Pool))
+			if s.Scanner != nil {
+				admin.Post("/scan", s.handleAdminScan)
+			}
 		})
 		subsonic.Mount(r, s.Pool, s.Logger, s.SubsonicCfg)
 	}