`medewerker-login.ts` becomes `keycloak-login.ts`: the three citizen specs
each duplicated the same three-line password login, so a fix to the login path
had to be made four times. They now call `loginBurger`, and both realms share
`submitPassword`.
No behaviour change — all 6 specs green against a live stack.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
