chore: add custom samesite options to auth cookies (#16885)

Allows controlling `samesite` cookie settings from the deployment config

coderd/workspaceapps/provider.go

@@ -22,6 +22,7 @@ const (
 type ResolveRequestOptions struct {
 	Logger              slog.Logger
 	SignedTokenProvider SignedTokenProvider
+	CookieCfg           codersdk.HTTPCookieConfig
 
 	DashboardURL   *url.URL
 	PathAppBaseURL *url.URL
@@ -75,12 +76,12 @@ func ResolveRequest(rw http.ResponseWriter, r *http.Request, opts ResolveRequest
 	//
 	// For subdomain apps, this applies to the entire subdomain, e.g.
 	//   app--agent--workspace--user.apps.example.com
-	http.SetCookie(rw, &http.Cookie{
+	http.SetCookie(rw, opts.CookieCfg.Apply(&http.Cookie{
 		Name:    codersdk.SignedAppTokenCookie,
 		Value:   tokenStr,
 		Path:    appReq.BasePath,
 		Expires: token.Expiry.Time(),
-	})
+	}))
 
 	return token, true
 }