v0.3.1 — self-healing cron scheduling (PRV_Cron_Guard)

Add PRV_Cron_Guard: idempotent init-hook guard that re-schedules
prv_weekly_probe and prv_daily_prune when missing (e.g. after
an rsync deploy that bypasses the activation hook).

- New class: includes/core/class-prv-cron-guard.php
  - Hooks on init; two wp_next_scheduled() checks on hot path
  - Delegates to PRV_Cron::schedule() and PRV_Prune_Cron::schedule()
    so recurrence + offset are always canonical (no inline divergence)
  - Idempotent: no-op when events already scheduled
- PRV_Plugin::init(): wires PRV_Cron_Guard::register_hooks()
- Tests: tests/unit/test-cron-guard.php (missing, idempotent, recurrence)
- Bump version 0.3.0 -> 0.3.1 (header + PRV_VERSION constant + bootstrap)
- CHANGELOG: [0.3.1] entry

pr-vision.php

@@ -3,7 +3,7 @@
  * Plugin Name: PR Vision
  * Plugin URI:  https://peptiderepo.com
  * Description: Weekly server-side LLM probes for AI-visibility (GEO) tracking. Records whether peptiderepo.com is cited by LLMs across core peptides, stores time-series, and renders an admin dashboard + settings UI.
- * Version:     0.3.0
+ * Version:     0.3.1
  * Author:      peptiderepo
  * Author URI:  https://peptiderepo.com
  * License:     GPL-2.0-or-later
@@ -24,7 +24,7 @@ if ( ! defined( 'ABSPATH' ) ) {
 
 /* ── Constants ────────────────────────────────────────────────────────── */
 
-define( 'PRV_VERSION', '0.3.0' );
+define( 'PRV_VERSION', '0.3.1' );
 define( 'PRV_PLUGIN_FILE', __FILE__ );
 define( 'PRV_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );
 define( 'PRV_PLUGIN_URL', plugin_dir_url( __FILE__ ) );