Development environment after the tasklie realm switch: dev UI issuer and a dev test account

gitops#93 points the backend, in both dev and production, at the new Keycloak realm (https://auth.taskl.ie/realms/tasklie).

What's broken in dev

• Dev's UI issuer comes from Infisical (project tasklie, env dev, /development/tasklie-ui-secrets) and still points at the old minecraft realm, so dev's backend rejects dev's tokens. Signed-in dev is broken until this is fixed.
• The dev smoke-test account tasklie-dev-tester lives in the minecraft realm. Recreate it in the tasklie realm (password in ~/.config/tasklie-dev-tester/password; never paste it) and keep it the owner of the "UI Test Lab" dev workspace.

Then

• Re-run the signed-in Playwright smoke test (24 routes) against dev.

Related: PAR-447 (sign out cleanly when the refresh fails).