✨ feature: Add calendar layout and occurrence handling functionality

- Introduced `calendar-layout.php` to manage month grid generation, occurrence intersection checks, and segment assignments for events.
- Added `occurrences.php` for normalizing, validating, and displaying event occurrences, including migration from legacy formats.
- Implemented functions for parsing dates, validating occurrence ranges, and formatting occurrences for display.
- Established hooks for synchronizing event occurrence data upon saving posts and validating ACF repeater fields.

includes/template-loader.php

@@ -9,6 +9,23 @@ if ( ! defined( 'ABSPATH' ) ) {
 	exit; // Exit if accessed directly.
 }
 
+/**
+ * Build safe contact-email markup for event templates.
+ *
+ * @param mixed $value Raw contact email value.
+ * @return string Escaped mailto anchor, or an empty string for invalid input.
+ */
+function aa_events_contact_email_markup( $value ) {
+	$raw   = trim( (string) $value );
+	$email = sanitize_email( $raw );
+	if ( '' === $email || $email !== $raw ) {
+		return '';
+	}
+
+	$protected = antispambot( $email );
+	return '<a href="' . esc_attr( 'mailto:' . $protected ) . '">' . wp_kses_post( $protected ) . '</a>';
+}
+
 /**
  * Load a template.
  *