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_scope_registrations_test.go

@@ -0,0 +1,70 @@
+// 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 iam_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"go.probo.inc/probo/pkg/accessreview"
+	"go.probo.inc/probo/pkg/agentrun"
+	"go.probo.inc/probo/pkg/coredata"
+	"go.probo.inc/probo/pkg/iam"
+	"go.probo.inc/probo/pkg/probo"
+)
+
+func allRegisteredOAuth2ScopeSets() *iam.ScopeSet {
+	return iam.NewScopeSet().
+		Merge(iam.IAMOAuth2ScopeSet()).
+		Merge(probo.OAuth2ScopeSet()).
+		Merge(accessreview.OAuth2ScopeSet()).
+		Merge(agentrun.OAuth2ScopeSet())
+}
+
+func registerAllOAuth2ScopeSets(authorizer *iam.Authorizer) {
+	authorizer.RegisterScopes(iam.IAMOAuth2ScopeSet())
+	authorizer.RegisterScopes(probo.OAuth2ScopeSet())
+	authorizer.RegisterScopes(accessreview.OAuth2ScopeSet())
+	authorizer.RegisterScopes(agentrun.OAuth2ScopeSet())
+}
+
+func TestRegisteredOAuth2ScopeSets_OrganizationRead(t *testing.T) {
+	t.Parallel()
+
+	authorizer := iam.NewAuthorizer(nil, nil)
+	registerAllOAuth2ScopeSets(authorizer)
+
+	scopeSet := allRegisteredOAuth2ScopeSets()
+	tokenScopes := coredata.OAuth2Scopes{probo.ScopeV1OrgRead}
+
+	assert.True(t, scopeSet.Allows(tokenScopes, probo.ActionOrganizationGet))
+	assert.False(t, scopeSet.Allows(tokenScopes, probo.ActionOrganizationUpdate))
+	assert.False(t, scopeSet.Allows(tokenScopes, probo.ActionThirdPartyList))
+}
+
+func TestRegisteredOAuth2ScopeSets_UnmappedActionDenies(t *testing.T) {
+	t.Parallel()
+
+	authorizer := iam.NewAuthorizer(nil, nil)
+	registerAllOAuth2ScopeSets(authorizer)
+
+	scopeSet := allRegisteredOAuth2ScopeSets()
+	tokenScopes := coredata.OAuth2Scopes{
+		probo.ScopeV1OrgRead,
+		probo.ScopeV1ThirdPartyRead,
+	}
+
+	assert.False(t, scopeSet.Allows(tokenScopes, "core:unmapped:action"))
+}