lib/hook-helpers.sh exports BEADS_DOLT_SERVER_PORT with override via
${BEADS_DOLT_SERVER_PORT:-3307} so users can still override per shell.
All hooks that source hook-helpers.sh automatically inherit the port.
scripts/bd-audit.sh and scripts/bd-cluster.sh are standalone bd callers
that do not source hook-helpers.sh, so they get the same export inline.
cli/embedded/lib/hook-helpers.sh synced via make sync-hooks.
Consumes ag-co7 'Export BEADS_DOLT_SERVER_PORT=3307 in shell env'.