fix: resolve BW state sync issue -- add sync() to login lifecycle

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).

docker-compose.yml

@@ -9,3 +9,7 @@ services:
       - ./agents.yaml:/app/agents.yaml:ro
       - ./state:/app/state
       - ./bw-state:/home/provision/.config/Bitwarden CLI
+      - ./bw_helper.py:/app/bw_helper.py:ro
+      - ./provision-agent.py:/app/provision-agent.py:ro
+      - ./test_bw_helper.py:/app/test_bw_helper.py:ro
+      - ./test_bw_persistence.py:/app/test_bw_persistence.py:ro