Add userName and externalID support

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

pkg/coredata/migrations/20260306T120000Z.sql

@@ -0,0 +1,16 @@
+ALTER TABLE iam_membership_profiles
+ADD COLUMN user_name TEXT,
+ADD COLUMN external_id TEXT;
+
+UPDATE iam_membership_profiles p
+SET user_name = i.email_address
+FROM identities i
+WHERE i.id = p.identity_id AND p.source = 'SCIM';
+
+CREATE UNIQUE INDEX idx_profiles_user_name_organization_id
+ON iam_membership_profiles (user_name, organization_id)
+WHERE user_name IS NOT NULL;
+
+CREATE UNIQUE INDEX idx_profiles_external_id_organization_id
+ON iam_membership_profiles (external_id, organization_id)
+WHERE external_id IS NOT NULL;