starknet_transaction_prover: bump prover_panics_total on panic hook fire

[avi-starkware]

Bumps the new prover_panics_total counter from the panic hook before
constructing the backtrace, so dashboards can alert on panic rate without
log search. The pre-registered zero observation in install_exporter
keeps the series visible at scrape time even before the first panic.

Co-Authored-By: Claude Opus 4.7 (1M context) noreply@anthropic.com

[cursor]

PR Summary

Low Risk
Observability-only changes to the panic hook and metrics registration; no change to proving, RPC, or request handling behavior.

Overview
Adds prover_panics_total Prometheus observability so panic rate can be alerted on without log search.

The global panic hook now increments that counter first (before backtrace capture and structured tracing output), so a recursive panic during hook work still records the original event. install_exporter pre-registers the series at zero like other counters so it appears on /metrics before the first panic.

A unit test asserts install_panic_hook bumps the counter by one when a panic is caught.

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[avi-starkware]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• starknet_transaction_prover: document observability surface in README #14203
• starknet_transaction_prover: origin-level breadcrumbs for validation errors #14172
• starknet_transaction_prover: /health returns 503 when service is saturated #14171
• starknet_transaction_prover: bump prover_panics_total on panic hook fire #14170 👈 (View in Graphite)
• starknet_transaction_prover: HTTP request count + latency + in-flight metrics #14169
• starknet_transaction_prover: proving-job duration + outcome metrics #14168
• starknet_transaction_prover: Prometheus /metrics endpoint with build_info #14167
• starknet_transaction_prover: global panic hook + graceful SIGTERM shutdown #14166
• starknet_transaction_prover,tower_ohttp: OHTTP-unlinkable request-id for decapsulated content #14222
• starknet_transaction_prover: per-request structured log with request-id #14165
• starknet_transaction_prover: unify HTTP middleware stack via macro #14286
• main-v0.14.3

This stack of pull requests is managed by Graphite. Learn more about stacking.

[reviewable-StarkWare]

This change is 

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

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[cursor]

Panic tests race global hook

Medium Severity

This module now has two separate #[test] functions that each call take_hook, set_hook, and catch_unwind on the process-global panic hook. Cargo runs those tests in parallel by default, so one test can restore or replace the hook while the other is mid-flight and panic_hook_bumps_panics_total_counter may see zero prover_panics_total delta.

 

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[cursor]

Counter before recorder installed

Low Severity

The panic hook now increments prover_panics_total on every panic, but main still calls install_panic_hook before install_exporter. Panics in that gap hit the hook while the Prometheus recorder is not installed yet, so those increments are not reflected in scrapes and panic-rate alerts can undercount.

 

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