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/lib/config.secret.example.php

@@ -0,0 +1,10 @@
+<?php
+// Vorlage: nach config.secret.php kopieren und mit echten Werten füllen.
+// config.secret.php niemals ins Repo/Backup geben.
+return [
+    'db_user'       => 'DEIN_DB_BENUTZER',
+    'db_password'   => 'DEIN_DB_PASSWORT',
+    'smtp_password' => 'DEIN_SMTP_PASSWORT',
+    // Produktiv auf die echte omsorgCore-URL überschreiben (Default in config.php ist localhost, nur für lokale Entwicklung):
+    // 'omsorg_core_url' => 'https://core.omsorg-pflegedienste.de',
+];