Add owner-only logging and Brickset API call tracking

LIM configured no logging at all, so the instruction fetcher had no trail to follow. Adds a rotating file handler on the root logger plus two owner-only admin pages.

- Admin > Logs: filter by level, source and text; tracebacks kept with their error; auto-refresh, raw download, rotated-file browsing and rotate-now

- Admin > Logs > Brickset API calls: every outbound call recorded with method, params, caller, duration, result count and error, plus daily quota accounting (only getSets counts) and a comparison against getKeyUsageStats

- New owner concept (services/ownership.py): a single account, distinct from is_admin, since these pages expose other admins activity. Defaults to the first admin; flask owner show/set to change

- Services now log through module loggers; retention setting and pruning for call records

- New CLI: flask owner show/set, flask logs path/prune

- New table brickset_api_calls, created automatically at boot; LOG_* env vars, /data/logs in Docker

docker/entrypoint.sh

@@ -15,7 +15,8 @@ log() { echo "[entrypoint] $*"; }
 # A freshly created named volume mounts as root:root, so the app user cannot
 # write to it until we hand it over. Cheap to repeat on every start.
 if [ "$(id -u)" = '0' ]; then
-    mkdir -p "${UPLOAD_FOLDER:-/data/uploads}" "${BACKUP_FOLDER:-/data/backups}"
+    mkdir -p "${UPLOAD_FOLDER:-/data/uploads}" "${BACKUP_FOLDER:-/data/backups}" \
+             "${LOG_FOLDER:-/data/logs}"
     chown -R "${APP_USER}:${APP_USER}" /data
 fi