refactor(2meet-data-optimizer): stop registering the sso group in core

- TMDO_Member_Fields no longer registers user/sso; the definition moved
  unchanged (hash 03543f19) to 2meet-data-optimizer-sso-addon.
- missing_integration_addons(): 2meet-hub-core or 2meet-spoke-sso without
  the SSO AddOn is reported (admin notice + Site Health).
- The deprecated-AddOn notice points hub / spoke users to the SSO AddOn.
- Sites must activate the SSO AddOn before this ships (PR-041); aeav_only
  sites without it fall back to orphan-group restore.
- Verify: core unit 659 / integration 475, SSO 6, HP 142/49, WC 10/22
  green, phpcs clean
- PR: PR-040

tests/unit/DeprecatedAddonsNoticeTest.php

@@ -43,6 +43,17 @@ class DeprecatedAddonsNoticeTest extends TestCase {
 		$this->assertStringContainsString( 'PARTNER-REGISTRATION.md', $html );
 	}
 
+	public function test_hub_and_spoke_point_to_the_sso_addon(): void {
+		$GLOBALS['_wp_options']['active_plugins'] = array( '2meet-data-optimizer-spoke-addon/2meet-data-optimizer-spoke-addon.php' );
+
+		ob_start();
+		TMDO_Deprecated_Addons_Notice::render();
+		$html = (string) ob_get_clean();
+
+		$this->assertStringContainsString( '2meet-data-optimizer-spoke-addon', $html );
+		$this->assertStringContainsString( '2meet-data-optimizer-sso-addon', $html );
+	}
+
 	public function test_no_notice_when_none_active_or_user_cannot_manage(): void {
 		ob_start();
 		TMDO_Deprecated_Addons_Notice::render();

tests/unit/MemberFields/MemberFieldsRegistrationTest.php

@@ -39,12 +39,18 @@ class MemberFieldsRegistrationTest extends TestCase {
 	public function test_all_four_groups_are_registered(): void {
 		WPDO_Member_Fields::register_entity_fields();
 
-		foreach ( array( 'membership', 'activity', 'profile', 'sso' ) as $group ) {
+		foreach ( array( 'membership', 'activity', 'profile' ) as $group ) {
 			$fields = WPDO_Entity_Registry::get_group_fields( 'user', $group );
 			$this->assertNotEmpty( $fields, "Group '{$group}' should have registered fields." );
 		}
 	}
 
+	public function test_core_leaves_the_sso_group_to_the_sso_addon(): void {
+		WPDO_Member_Fields::register_entity_fields();
+
+		$this->assertSame( array(), WPDO_Entity_Registry::get_group_fields( 'user', 'sso' ) );
+	}
+
 	public function test_core_registers_no_hp_user_group(): void {
 		WPDO_Member_Fields::register_entity_fields();
 
@@ -148,41 +154,6 @@ class MemberFieldsRegistrationTest extends TestCase {
 		$this->assertTrue( (bool) $field['fulltext'] );
 	}
 
-	// ── sso group ────────────────────────────────────────────────────────────
-
-	public function test_sso_group_has_eight_fields(): void {
-		WPDO_Member_Fields::register_entity_fields();
-		$fields = WPDO_Entity_Registry::get_group_fields( 'user', 'sso' );
-		// v3.4.4: known_login_ips registered (was leaking to wp_usermeta via set_entity).
-		$this->assertCount( 8, $fields );
-		$this->assertNotNull( $this->find_field( $fields, 'known_login_ips' ) );
-	}
-
-	public function test_hub_global_user_id_is_searchable(): void {
-		WPDO_Member_Fields::register_entity_fields();
-		$fields = WPDO_Entity_Registry::get_group_fields( 'user', 'sso' );
-		$field  = $this->find_field( $fields, 'hub_global_user_id' );
-
-		$this->assertTrue( (bool) $field['searchable'] );
-	}
-
-	public function test_token_expires_at_is_datetime_searchable(): void {
-		WPDO_Member_Fields::register_entity_fields();
-		$fields = WPDO_Entity_Registry::get_group_fields( 'user', 'sso' );
-		$field  = $this->find_field( $fields, 'token_expires_at' );
-
-		$this->assertSame( 'datetime', $field['type'] );
-		$this->assertTrue( (bool) $field['searchable'] );
-	}
-
-	public function test_refresh_token_enc_is_textarea(): void {
-		WPDO_Member_Fields::register_entity_fields();
-		$fields = WPDO_Entity_Registry::get_group_fields( 'user', 'sso' );
-		$field  = $this->find_field( $fields, 'refresh_token_enc' );
-
-		$this->assertSame( 'textarea', $field['type'] );
-	}
-
 	// ── register() hooks add_action ──────────────────────────────────────────
 
 	public function test_register_hooks_wpdo_register_entity_fields(): void {

tests/unit/MissingIntegrationAddonsTest.php

@@ -79,6 +79,27 @@ class MissingIntegrationAddonsTest extends TestCase {
 		$this->assertSame( array( 'WooCommerce' => '2meet-data-optimizer-woocommerce-addon' ), TMDO_Compatibility::missing_integration_addons() );
 	}
 
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_hub_or_spoke_without_the_sso_addon_is_reported(): void {
+		eval( 'final class TMSO_Plugin {}' );
+
+		$this->assertSame( array( '2meet Hub / Spoke SSO' => '2meet-data-optimizer-sso-addon' ), TMDO_Compatibility::missing_integration_addons() );
+	}
+
+	/**
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_hub_with_the_sso_addon_is_fine(): void {
+		eval( 'final class TMHC_Plugin {}' );
+		eval( 'final class TMDO_SSO_Integration {}' );
+
+		$this->assertSame( array(), TMDO_Compatibility::missing_integration_addons() );
+	}
+
 	/**
 	 * @runInSeparateProcess
 	 * @preserveGlobalState disabled