Migrate omsorgapp to browser SPA, add Docker/CI build setup

- omsorgapp: drop Electron, run as a plain Vite/React browser app; refresh
  token moves to an HttpOnly cookie (omsorgCore), CORS added for the new
  browser origin, document download/preview switched to Blob-based browser
  APIs.
- Add Dockerfiles for omsorgCore, omsorgapp, and omsorgWeb, a docker-compose.yml
  wiring Postgres/MySQL/all three apps together, and a Gitea Actions workflow
  that builds and pushes images to the repo's container registry on push to
  main and on version tags.

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

omsorgapp/src/components/Sidebar.jsx

@@ -10,7 +10,10 @@ import {
   BarChart3,
   Settings,
   Bug,
-  ScrollText
+  ScrollText,
+  Trash2,
+  CalendarOff,
+  Clock
 } from "lucide-react";
 import { useAuth } from "../app/AuthContext";
 import { isNavItemVisible } from "../app/navPermissions";
@@ -20,13 +23,16 @@ const menu = [
   { icon: Users, label: "Mitarbeiter" },
   { icon: Building2, label: "Kunden" },
   { icon: CalendarDays, label: "Disposition" },
+  { icon: CalendarOff, label: "Abwesenheiten" },
+  { icon: Clock, label: "Zeiterfassung" },
   { icon: Calculator, label: "Kalkulation" },
   { icon: Car, label: "Fahrzeuge" },
   { icon: FileText, label: "Rechnungen" },
   { icon: BarChart3, label: "Controlling" },
   { icon: Settings, label: "Einstellungen" },
   { icon: Bug, label: "Debug" },
-  { icon: ScrollText, label: "Audit-Log" }
+  { icon: ScrollText, label: "Audit-Log" },
+  { icon: Trash2, label: "Papierkorb" }
 ];
 
 export default function Sidebar({