fix(abilities): get-instructions description matches its tier-gated payload (#133)

The behavior shipped in #87 — plugin inventory rides the context only at
the admin tier — but the description still promised "its setup and
active plugins" unconditionally, and that line is what the WordPress.org
reviewer quoted. Descriptions are the agent-facing interface; this one
now states the tier condition.

Regenerating the pot also picks up the cookbook strings it had gone
stale against — the exact missing-feature failure CLAUDE.md warns about.

Refs #132

Author: ifahimreza

includes/abilities/core-content.php

@@ -60,7 +60,7 @@ function saddle_register_abilities() {
 		'saddle/get-instructions',
 		array(
 			'label'               => __( 'Get instructions', 'saddle' ),
-			'description'         => __( 'Returns important context about this site (its setup and active plugins) and the site owner\'s instructions for AI agents. Call this first, before other actions, and follow the guidance it returns. Read-only.', 'saddle' ),
+			'description'         => __( 'Returns important context about this site and the site owner\'s instructions for AI agents. Call this first, before other actions, and follow the guidance it returns. The installed-plugin inventory is included only for admin-level credentials. Read-only.', 'saddle' ),
 			'category'            => 'saddle',
 			'input_schema'        => array(
 				'type'       => 'object',