metrics(site-explorer): instrument endpoint update path

[williampnvidia]

Summary

• add update_explored_endpoints subphase timings to the existing site explorer phase latency histogram
• add per-endpoint exploration step latency for Redfish probing, error-context load, and report enrichment
• add last-run update_explored_endpoints counts for loaded records, candidate classes, selected endpoints, DB write attempts, firmware update attempts, and Redfish remediation candidates

Validation

• PASS: cargo +nightly-2026-06-16 fmt --all -- --check
• PASS: cargo check -p carbide-site-explorer
• PASS: cargo clippy -p carbide-site-explorer --lib -- -D warnings
• Needs martindev rerun for current SHA: CARGO_HOME="$HOME/.cargo" cargo make --no-workspace clippy-flow

Supersedes draft PR #2888, whose PR metadata stayed pinned to the old force-pushed head SHA.

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ℹ️ Recent review info

⚙️ Run configuration

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Plan: Enterprise

Run ID: cef213d4-73f1-4b5f-8932-e818abed34e1

📥 Commits

Reviewing files that changed from the base of the PR and between 6a2db3d and a51b191.

📒 Files selected for processing (2)

• crates/site-explorer/src/lib.rs
• crates/site-explorer/src/metrics.rs

🚧 Files skipped from review as they are similar to previous changes (2)

• crates/site-explorer/src/metrics.rs
• crates/site-explorer/src/lib.rs

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Summary by CodeRabbit

• New Features
  • Added finer-grained site exploration telemetry, including per-step latency tracking across the update-explored-endpoints workflow.
  • Exposed additional metrics for exploration planning/candidates/selection, persistence operation counts, and remediation candidate volume.
  • Introduced new telemetry instruments to publish step-latency histograms and update-explored-endpoints count gauges.
• Bug Fixes
  • Improved metrics emission by clearing step-latency data after recording to prevent accumulation across metric updates.

Walkthrough

The PR adds step-level exploration timings, phase latency counters, and per-run counts to site explorer metrics. It also threads these measurements through task execution, planning, persistence, and remediation.

Changes

Site explorer metrics instrumentation

Layer / File(s)	Summary
Metrics storage and instrument wiring crates/site-explorer/src/metrics.rs	SiteExplorationMetrics stores step latencies and last-run counts, and SiteExplorerInstruments exports them through a histogram and observable gauge.
Load and selection phase metrics crates/site-explorer/src/lib.rs	update_explored_endpoints records load, preallocation, interface/index build, candidate, and selection phase counts and latencies.
Per-endpoint exploration step timing crates/site-explorer/src/lib.rs	Each spawned exploration task tracks Redfish, failure-context, and report-enrichment durations and returns them in a structured result.
Result aggregation, persistence, and remediation crates/site-explorer/src/lib.rs	Task-result aggregation emits per-step latencies and records explicit persistence counters plus persistence and remediation latencies.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the endpoint update metrics instrumentation change.
Description check	✅ Passed	The description matches the added site-explorer timing and count metrics.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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[github-actions]

🔍 Container Scan Summary

Service	Total	Critical	High	Medium	Low	Other
boot-artifacts-aarch64	3	0	0	3	0	0
boot-artifacts-x86_64	3	0	0	3	0	0
forge-admin-cli-x86_64	283	6	24	98	7	148
machine-validation-runner	744	32	188	267	36	221
machine_validation	744	32	188	267	36	221
machine_validation-aarch64	744	32	188	267	36	221
nvmetal-carbide	744	32	188	267	36	221
TOTAL	3265	134	776	1172	151	1032

Per-CVE detail lives in the per-service grype-* artifacts (JSON + SARIF). Severity counts only — no CVE IDs published here.

[github-actions]

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