Add SSO login support via mcdsl/sso

When [sso].redirect_uri is configured, the web UI shows a "Sign in
with MCIAS" button instead of the username/password form. Upgrades
mcdsl to v1.7.0 which includes the Firefox cookie fix.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cmd/mcq/server.go

@@ -77,6 +77,9 @@ func runServer(configPath string) error {
 	wsCfg := webserver.Config{
 		ServiceName: cfg.MCIAS.ServiceName,
 		Tags:        cfg.MCIAS.Tags,
+		MciasURL:    cfg.MCIAS.ServerURL,
+		CACert:      cfg.MCIAS.CACert,
+		RedirectURI: cfg.SSO.RedirectURI,
 	}
 	webSrv, err := webserver.New(wsCfg, database, authClient, logger)
 	if err != nil {