chore: remove daemon token authentication

The Ed25519 JWT verifier was only reachable through the sandd-controller
binary and FFI removed in #42; the Python Server never enabled it. Authz is
expected to move to Keycloak, whose tokens need different verification, so
drop the verifier, the jsonwebtoken dependency and the daemon's SANDD_TOKEN
bearer header rather than keep dead code. Empty daemon ids are still refused.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: kerthcet <kerthcet@gmail.com>

Author: kerthcet