Deep update for l2tp, firewall, vpp, appliance, and monitoring
l2tp: rewrite with RADIUS auth/acct/CoA, IP pools, traffic shaping,
CQM metrics, session observer, Prometheus metrics, web UI, kernel
integration detail, and environment variables.
firewall: rewrite with full match/action tables, VPP backend (NAT44-ED,
ACL classify), named sets with timeouts, NAT exclude pattern.
vpp: MPLS label programming now implemented (was "not yet wired"),
add firewall VPP backend cross-reference, update roadmap table.
appliance: add ze appliance management CLI (init, build, push,
config-push with auto-revert, export/import, batch parallel ops).
monitoring: add OS metrics (Netdata-compatible collectors), host
hardware metrics (ze_host_* namespace), diagnostics section (FSM
history, capture rings, VPP trace, active probes, structured log
query, component health endpoint).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>