feat: establish v0.70 platform milestone

migrations/000042_operator_accounts.up.sql

@@ -0,0 +1,24 @@
+BEGIN;
+
+ALTER TABLE user_account
+    ADD COLUMN account_kind varchar(24) NOT NULL DEFAULT 'customer'
+    CHECK (account_kind IN ('customer','operator'));
+
+UPDATE user_account
+SET account_kind='operator'
+WHERE platform_role <> 'customer';
+
+ALTER TABLE user_account
+    ADD CONSTRAINT user_account_kind_role_check CHECK (
+        (account_kind='customer' AND platform_role='customer') OR
+        (account_kind='operator' AND platform_role IN ('ops_viewer','ops_operator','ops_approver','ops_admin'))
+    );
+
+CREATE INDEX user_account_operator_identity_idx
+    ON user_account(oidc_issuer,oidc_subject,tenant_id)
+    WHERE account_kind='operator' AND status='active';
+
+COMMENT ON COLUMN user_account.account_kind IS
+    'Hard boundary between household customer identities and dedicated maintenance operator identities.';
+
+COMMIT;