feat(anchor): expose Anchor Prometheus metrics on port 5164

[shane-moore]

What this adds

Starts Anchor nodes with --metrics and publishes port 5164, so duty timing, head-event
trigger counters, and QBFT instrumentation are readable on a local run. SSV nodes already
publish theirs (port 9240, nodes/ssv/node.star); this closes that asymmetry and follows the
same shape there: module-level name/number constants plus a PortSpec in the ports dict.

16 lines in one file, no params or profile changes.

Why the explicit 0.0.0.0

Anchor defaults the metrics listen address to 127.0.0.1 (--metrics-address help: "Defaults
to 127.0.0.1 if --metrics is set"). Bound to loopback inside the container, the published port
refuses connections, so the bind has to be explicit.

Image compatibility

--metrics / --metrics-address / --metrics-port are present on every anchor image pinned in
this repo, checked against the shipped binaries rather than the source:

• sigp/anchor:v1.3.0 (params.yaml, params-boole.yaml)
• sigp/anchor:v1.2.0 (params-gloas.yaml)

Both default to port 5164. No profile regresses; profiles with anchor.count: 0 are unaffected
either way.

Verification

Live 4-operator all-Anchor run (ssv: 0 / anchor: 4):

• kurtosis enclave inspect shows metrics: 5164/tcp on all four anchor-node-N, not just
  the bootnode (nodes 1..n inherit the flags via the existing list(command_arr) copy, and the
  ports dict is set on both service configs).
• curl http://127.0.0.1:<mapped>/metrics returns HTTP 200 on all four, ~3,600 lines of
  Prometheus text each, carrying real Anchor families: anchor_execution_current_block,
  anchor_processor_work_event_queue_length, anchor_processor_worker_time_*.

Context

Extracted from #33 per @iurii-ssv's review. That PR's Gloas profiles are superseded by the work
merged since (#34, #35, #36, #37, #39, #40, #41), and this metrics change was one of the two
pieces identified as still net-new. The other, the buildoor external-builder profile, is left
out: it needs builder_count, which is absent from ethereum-package@6.1.0, and upstream still
starts genesis builders at actual_num_validators, colliding with the preregistered keyshare
validators at 64-73. That needs an upstream fix first rather than pinning this repo to a fork.