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).

Dockerfile

@@ -23,8 +23,8 @@ RUN wget -q -O /tmp/bw.zip \
 COPY requirements.txt /tmp/
 RUN python3 -m pip install --no-cache-dir --break-system-packages -r /tmp/requirements.txt
 
-# Create non-root user for Playwright
-RUN groupadd -r provision && useradd -r -g provision -G audio,video -m -d /home/provision provision \
+# Create non-root user for Playwright, matching host UID/GID for bind-mount access
+RUN groupadd -r -g 1002 provision && useradd -r -u 1002 -g provision -G audio,video -m -d /home/provision provision \
     && mkdir -p "/home/provision/.config/Bitwarden CLI" \
     && chown -R provision:provision /home/provision