refactor(preingestion): let firmware upload results move their counter

[chet]

I was walking the preingestion firmware upload fallback and noticed every terminal result already had both halves of an Event: a {method,outcome} counter observation, and a nearby record explaining the failure. Multipart being unsupported is the fun edge -- it is a real multipart outcome and then an HttpPush attempt, so flattening the flow would lose useful history.

So, this gives the upload outcomes typed Events that own both signals. FirmwareUploadFinished dynamically keeps each historical failure level and message, while successful uploads stay metric-only. The unsupported multipart path gets a sibling Event so its fallback-specific WARN keeps the exact schema operators already know.

carbide_preingestion_firmware_upload_total, its description, and every method/outcome label stay put. BMC addresses and error details stay in log-only context. Most importantly, multipart fallback still records two honest observations -- the unsupported multipart result, followed by the HttpPush result -- because that is what actually happened.

And yep, the fallback sequence has a test! I ran:

• cargo test -p carbide-preingestion-manager
• cargo make format-nightly
• cargo make clippy
• cargo make carbide-lints
• cargo make check-event-names
• cargo xtask check-metric-docs

The local CodeRabbit and independent Claude passes were clean, too.

This supports #3734

Closes #3734

[chet]

@coderabbitai full_review, thanks!

[coderabbitai]

Walkthrough

Preingestion firmware upload metrics now include BMC addresses and failure details, emit route-specific logs dynamically, distinguish unsupported multipart uploads, and validate counters and historical log output across upload methods.

Changes

Firmware upload observability

Layer / File(s)	Summary
Dynamic firmware upload instrumentation crates/preingestion-manager/src/metrics.rs	FirmwareUploadFinished carries BMC and error context with dynamic success/failure logging, while MultipartFirmwareUploadUnsupported records unsupported multipart attempts separately.
Upload-path metric emissions crates/preingestion-manager/src/lib.rs	SimpleUpdate, HttpPush, and multipart paths populate destination and error details; unsupported multipart paths emit the dedicated event.
Metric and log validation crates/preingestion-manager/src/metrics.rs	Table-driven tests verify counter deltas, route-specific failure logs, silent successes, and multipart warning behavior.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related issues

• Unify preingestion firmware upload logs and metrics #3734 — Covers unification of preingestion firmware upload metrics and logs, including multipart fallback behavior.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.
Title check	✅ Passed	The title is clearly related to the firmware upload refactor and the counter/logging behavior change.
Description check	✅ Passed	The description matches the changeset and explains the firmware upload event and fallback refactor.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

@chet: I’ll perform a complete re-review of the pull request. 🐇

✅ Action performed

Full review finished.