Remove stale Obsidian sync lock before starting continuous sync

The ob CLI uses a directory lock at .obsidian/.sync.lock that persists
across container restarts via the volume mount, causing "Another sync
instance is already running" errors. Remove it before starting sync.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

startup.sh

@@ -22,6 +22,8 @@ if [ "${OBSIDIAN_CONTINUOUS_SYNC}" = "true" ]; then
                --path "${VAULT_PATH}" \
                --password "${OBSIDIAN_E2E_PASSWORD}" \
                --device-name "${OBSIDIAN_DEVICE_NAME:-simbarag}"; then
+            # Remove stale lock from previous container run
+            rm -rf "${VAULT_PATH}/.obsidian/.sync.lock"
             # Start continuous sync in background
             echo "Starting Obsidian continuous sync..."
             ob sync --continuous --path "${VAULT_PATH}" &