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/service-worker.js

@@ -0,0 +1,13 @@
+const CACHE = 'omsorg-v1';
+const STATIC = ['./app.css'];
+
+self.addEventListener('install', e =>
+  e.waitUntil(caches.open(CACHE).then(c => c.addAll(STATIC)))
+);
+
+self.addEventListener('fetch', e => {
+  if (e.request.url.endsWith('.php') || e.request.method !== 'GET') return;
+  e.respondWith(
+    fetch(e.request).catch(() => caches.match(e.request))
+  );
+});