Add docstrings to all handler functions in daemon/handlers/firewall.py, covering
params, return values, and raised exceptions. Add inline comments to
_config_apply() reconciliation steps and the request body merge order.
Add docstrings across lib/ modules for emit helpers (_emit_str, _emit_int, etc.),
volatile stripping logic, two-layer diff strategy, sync event dispatch, and all
cross-subsystem sync subscribers (DnsToFirewall, WgToFirewall, FirewallToDhcp,
NetworkToAllSync).
Document WireGuard/networkd config parsers and key-value mappers in
system_import.py. Add docstrings to _ep(), Registry.decorator,
setup_logging, and _replace helper across daemon/ and lib/.
mteehan
c21639b7f1