Reorganize into monorepo layout, move mitarbeiter-app to legacy reference

Consolidates the previously separate omsorgapp and omsorgCore repos
(each had their own nested .git with GitHub history) plus the old
root-level website/mitarbeiter-app into a single monorepo, matching
the structure already documented in the root CLAUDE.md. Also moves
the PHP employee app aside as omsorgWeb/mitarbeiter-app-legacy/ to
serve as a template for a ground-up rewrite.

Fixes .gitignore in the same pass: the config-secrets/uploads/data
patterns were unanchored (relative to repo root, not depth-agnostic),
so they silently stopped matching once the app moved under omsorgWeb/.
Patterns are now **/-prefixed and cover both mitarbeiter-app and
mitarbeiter-app-legacy, keeping DB/SMTP credentials and uploaded
employee documents out of version control.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

omsorgWeb/mitarbeiter-app-legacy/pages/fortbildung-serve.php

@@ -0,0 +1,25 @@
+<?php
+require_once __DIR__ . '/../lib/auth.php';
+require_login();
+
+$id = (int)($_GET['id'] ?? 0);
+if ($id <= 0) { http_response_code(400); echo 'Ungültige Anfrage.'; exit; }
+
+$stmt = db()->prepare('SELECT filename, original_name FROM fortbildung_materials WHERE id = ?');
+$stmt->execute([$id]);
+$row = $stmt->fetch();
+if (!$row) { http_response_code(404); echo 'Datei nicht gefunden.'; exit; }
+
+$path = dirname(__DIR__) . '/fortbildung-materials/' . $row['filename'];
+if (!is_file($path)) { http_response_code(404); echo 'Datei nicht gefunden.'; exit; }
+
+$safe_display = addslashes($row['original_name']);
+$safe_encoded = rawurlencode($row['original_name']);
+
+header('Content-Type: application/octet-stream');
+header('Content-Disposition: attachment; filename="' . $safe_display . '"; filename*=UTF-8\'\'' . $safe_encoded);
+header('Content-Length: ' . filesize($path));
+header('X-Content-Type-Options: nosniff');
+header('Cache-Control: private, no-store');
+readfile($path);
+exit;