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/modules/employees/EmployeeForm.jsx

@@ -73,6 +73,7 @@ export function employeeFormToPayload(form, { includeStatus = false } = {}) {
 export default function EmployeeForm({ form, onChange, includeStatus = false }) {
   const { items: statusOptions } = useValueListItems("EmployeeStatus");
   const { items: employmentTypes } = useValueListItems("EmploymentType");
+  const { items: qualifications } = useValueListItems("Qualification");
 
   function updateField(field) {
     return (event) => onChange({ ...form, [field]: event.target.value });
@@ -168,7 +169,14 @@ export default function EmployeeForm({ form, onChange, includeStatus = false })
 
       <label className="form-field">
         <span>Qualifikation</span>
-        <input value={form.qualification} onChange={updateField("qualification")} />
+        <select value={form.qualification} onChange={updateField("qualification")}>
+          <option value="">— nicht angegeben —</option>
+          {qualifications.map((option) => (
+            <option key={option.id} value={option.value}>
+              {option.value}
+            </option>
+          ))}
+        </select>
       </label>
 
       <fieldset className="form-field form-field--fieldset">