feat(03-03): create notification class with admin alert on job submission

- Created DDHH_JM_Notifications class with email notification system
- Hook into transition_post_status to detect new pending job submissions
- Send German email to admin with job details and edit link
- Email includes: title, author, org, location, type, date, edit link
- Only trigger on new → pending transition to avoid spam on updates
- Log errors if wp_mail() fails (common in Local WP)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

includes/class-notifications.php

@@ -0,0 +1,112 @@
+<?php
+/**
+ * Email notification system for job submissions
+ *
+ * @package DDHH_Job_Manager
+ */
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit;
+
+/**
+ * Handles email notifications for job submissions
+ */
+class DDHH_JM_Notifications {
+
+	/**
+	 * Setup notification hooks
+	 */
+	public static function setup_hooks() {
+		// Hook into post status transitions to detect new pending job submissions
+		add_action( 'transition_post_status', array( __CLASS__, 'send_admin_new_job_notification' ), 10, 3 );
+	}
+
+	/**
+	 * Send admin notification when a new job is submitted for moderation
+	 *
+	 * @param string  $new_status New post status.
+	 * @param string  $old_status Old post status.
+	 * @param WP_Post $post       Post object.
+	 */
+	public static function send_admin_new_job_notification( $new_status, $old_status, $post ) {
+		// Only trigger on job_offer posts transitioning to pending
+		if ( 'job_offer' !== $post->post_type ) {
+			return;
+		}
+
+		// Only send notification on initial submission to pending
+		// Avoid sending on every save when already pending
+		if ( 'pending' !== $new_status || 'pending' === $old_status ) {
+			return;
+		}
+
+		// Get admin email
+		$admin_email = get_option( 'admin_email' );
+		if ( ! $admin_email ) {
+			error_log( 'DDHH Job Manager: Cannot send admin notification - admin_email option not set' );
+			return;
+		}
+
+		// Prepare email data
+		$job_title = $post->post_title;
+		$author    = get_userdata( $post->post_author );
+		$author_name = $author ? $author->display_name : 'Unbekannt';
+		$author_org  = get_user_meta( $post->post_author, 'ddhh_org_name', true );
+		if ( empty( $author_org ) ) {
+			$author_org = 'Nicht angegeben';
+		}
+
+		// Get ACF fields
+		$job_location = get_field( 'job_location', $post->ID );
+		$job_type     = get_field( 'job_type', $post->ID );
+
+		// Get submission date
+		$submission_date = get_the_date( 'd.m.Y H:i', $post->ID );
+
+		// Get edit link
+		$edit_link = get_edit_post_link( $post->ID, '' );
+
+		// Build email subject
+		$subject = sprintf( 'Neues Stellenangebot zur Prüfung: %s', $job_title );
+
+		// Build email body
+		$body = sprintf(
+			"Ein neues Stellenangebot wurde eingereicht und wartet auf Ihre Prüfung.\n\n" .
+			"Titel: %s\n" .
+			"Anbieter: %s (%s)\n" .
+			"Standort: %s\n" .
+			"Art: %s\n" .
+			"Eingereicht am: %s\n\n" .
+			"Prüfen Sie das Stellenangebot hier:\n%s\n\n" .
+			"---\n" .
+			"Diese E-Mail wurde automatisch gesendet.",
+			$job_title,
+			$author_name,
+			$author_org,
+			$job_location ? $job_location : 'Nicht angegeben',
+			$job_type ? $job_type : 'Nicht angegeben',
+			$submission_date,
+			$edit_link
+		);
+
+		// Set email headers
+		$headers = array( 'Content-Type: text/html; charset=UTF-8' );
+
+		// Convert plain text to HTML with line breaks
+		$html_body = nl2br( esc_html( $body ) );
+
+		// Send email
+		$sent = wp_mail( $admin_email, $subject, $html_body, $headers );
+
+		// Log if email fails
+		if ( ! $sent ) {
+			error_log(
+				sprintf(
+					'DDHH Job Manager: Failed to send admin notification for job #%d "%s". Email may be disabled in Local WP environment.',
+					$post->ID,
+					$job_title
+				)
+			);
+		}
+	}
+}