feat(01-03): register ddhh_provider role with restricted capabilities

- Add DDHH_JM_Roles class with add_roles() and remove_roles() methods
- Role 'ddhh_provider' (Anbieter) can edit/delete own job_offers only
- Jobs go to pending status (publish_job_offers: false)
- No access to regular posts/pages (edit_posts/edit_pages: false)
- Can upload files for logos
- Integrated with Activator and Deactivator hooks

includes/class-activator.php

@@ -30,6 +30,9 @@ class DDHH_JM_Activator {
 		// Store plugin version
 		update_option( 'ddhh_jm_version', DDHH_JM_VERSION );
 
+		// Register custom roles
+		DDHH_JM_Roles::add_roles();
+
 		// Set flag to flush rewrite rules on next init
 		set_transient( 'ddhh_jm_flush_rewrite_rules', 1, 60 );
 	}