M3 Integration fixes

Modules/M3/Helpers/M3Auth.php

@@ -0,0 +1,36 @@
+<?php
+
+if (! function_exists('m3_user')) {
+    /**
+     * Return the current Core username in the format expected by the legacy M3 data.
+     * M3 previously depended on PHP Basic Auth and read PHP_AUTH_USER directly.
+     */
+    function m3_user(): string
+    {
+        $user = auth()->user();
+
+        $value = $user?->username
+            ?? $user?->user_name
+            ?? $user?->name
+            ?? $user?->email
+            ?? request()->server('PHP_AUTH_USER')
+            ?? '';
+
+        if (str_contains((string) $value, '@')) {
+            $value = strstr((string) $value, '@', true) ?: $value;
+        }
+
+        return strtoupper(trim((string) $value));
+    }
+}
+
+if (! function_exists('m3_legacy_password')) {
+    /**
+     * Passwords are intentionally unavailable in Core. PostgreSQL access uses
+     * Laravel's configured connection and never reuses a user's login password.
+     */
+    function m3_legacy_password(): string
+    {
+        return '';
+    }
+}