Add OAuth2 API scope registration and enforcement

Register v1 API scopes in coredata, advertise them in OIDC discovery
and protected-resource metadata, show them on the consent screen, and
enforce scope-to-action mapping in the IAM Authorizer before policy
evaluation.

Signed-off-by: Ludovic Vielle <ludovic@probo.com>

pkg/iam/oauth2/protected_resource_metadata_test.go

@@ -0,0 +1,45 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package oauth2_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.probo.inc/probo/pkg/coredata"
+	"go.probo.inc/probo/pkg/iam/oauth2"
+	"go.probo.inc/probo/pkg/probo"
+	"go.probo.inc/probo/pkg/uri"
+)
+
+func TestNewProtectedResourceMetadata(t *testing.T) {
+	t.Parallel()
+
+	apiScopes := []coredata.OAuth2Scope{probo.ScopeV1DocumentRead}
+
+	resource := uri.URI("https://app.example.com")
+	authorizationServer := uri.URI("https://app.example.com")
+
+	metadata := oauth2.NewProtectedResourceMetadata(resource, authorizationServer, apiScopes)
+	require.NotNil(t, metadata)
+
+	assert.Equal(t, resource, metadata.Resource)
+	assert.Equal(t, []uri.URI{authorizationServer}, metadata.AuthorizationServers)
+	assert.Equal(t, []string{"header"}, metadata.BearerMethodsSupported)
+	assert.Contains(t, metadata.ScopesSupported, oauth2.ScopeOpenID)
+	assert.Contains(t, metadata.ScopesSupported, probo.ScopeV1DocumentRead)
+	assert.NotContains(t, metadata.ScopesSupported, oauth2.ScopeProfile)
+}