The provisioner's BitwardenHelper.login() was missing the critical
`bw sync` step that the host wrapper includes. Without syncing after
login, the container's local vault cache was empty/stale, causing items
to vanish between container runs. Added sync() call at end of login()
and before list_items().
Also fixed container UID/GID to match host user (1002:1002) for proper
bind-mount access, and added source-code volume mounts for fast iteration.
Verified with 5-phase cross-container persistence test (create in
container A, verify in fresh container B, update in C, confirm in D).
