fix: staticcheck and go mod tidy

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

go.mod

@@ -6,6 +6,7 @@ require (
 	charm.land/bubbles/v2 v2.2.1
 	charm.land/bubbletea/v2 v2.1.0
 	charm.land/lipgloss/v2 v2.0.6
+	filippo.io/age v1.3.2
 	github.com/Azure/azure-sdk-for-go/sdk/azcore v1.23.3
 	github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.14.1
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/keyvault/armkeyvault/v2 v2.1.0
@@ -29,7 +30,6 @@ require (
 	cloud.google.com/go/auth v0.18.2 // indirect
 	cloud.google.com/go/auth/oauth2adapt v0.2.8 // indirect
 	cloud.google.com/go/compute/metadata v0.9.0 // indirect
-	filippo.io/age v1.3.2 // indirect
 	filippo.io/hpke v0.4.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/internal v1.13.0 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/security/keyvault/internal v1.2.0 // indirect