apollo_dashboard: alert on committer block number lag and block commit latency

[itamar-starkware]

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[reviewable-StarkWare]

This change is 

[cursor]

PR Summary

Low Risk
Dashboard and alert-definition changes only; no runtime committer or consensus logic is modified.

Overview
Adds committer health visibility and paging on two signals: how far the committer trails consensus, and how long single-block commits take.

The Committer Grafana row gains a per-namespace Committer Lag (blocks) timeseries (consensus_block_number - committer_offset, with pod filters stripped so cross-pod metrics compare correctly) and a Block Commit Latency histogram panel (p50/p95 from committer_block_commit_latency).

Two new block production delay alerts are wired into alert_definitions and exported in dev_grafana_alerts.json:

• committer_block_number_lag (p2, 5m): fires when lag exceeds 9 blocks, only on non-observer namespaces with no sync-driven consensus progress in the last 5m.
• committer_block_commit_latency_too_high (p4): fires when the 2m average commit latency exceeds ~9s, intended to catch slowdowns before lag builds.

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[itamar-starkware]

• apollo_batcher: debug-log compressed byte size of committer-returned commitment infos #14891
• apollo_dashboard: alert on committer block number lag and block commit latency #14890 👈 (View in Graphite)
• apollo_committer: add per-block commit latency histogram metric #14889
• apollo_committer,apollo_committer_config: warn when block commit exceeds duration threshold #14888
• main

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[yoavGrs]

@yoavGrs made 1 comment.
Reviewable status: 0 of 5 files reviewed, 1 unresolved discussion (waiting on dan-starkware and itamar-starkware).

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a discussion (no related file):
@dan-starkware Do we want a new alert where the gap between consensus and batcher is > 7?

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[yoavGrs]

@yoavGrs made 1 comment.
Reviewable status: 0 of 5 files reviewed, 2 unresolved discussions (waiting on dan-starkware and itamar-starkware).

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a discussion (no related file):
Please split this PR, one for each metric.