starknet_transaction_prover: per-request structured log with request-id

[avi-starkware]

Adds RequestLogLayer that emits one event="http_request" log line per
request with request_id, method, path, status, and latency_ms. The id is
accepted from x-request-id or generated as a 128-bit random hex string,
and is echoed back on the response so callers can quote it. No request
body bytes are inspected (transaction calldata is private user data).

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

[cursor]

PR Summary

Low Risk
Observability-only middleware with defensive header validation; no changes to proving, auth, or request body handling beyond logging metadata.

Overview
Adds RequestLogLayer as the outermost HTTP middleware on both plain and TLS JSON-RPC servers so every request gets one structured log line (event="http_request") with request_id, method, path, status, and latency_ms.

The layer accepts a client x-request-id when it is a short printable ASCII token (max 128 chars); otherwise it generates a 32-char hex id via rand, sets the header on the inbound request for downstream services, echoes it on the response, and never reads the body. Invalid or hostile ids (non-ASCII, whitespace, oversize) are replaced with a fresh generated id.

Exports REQUEST_ID_HEADER and adds unit tests for id propagation and sanitization.

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[reviewable-StarkWare]

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[avi-starkware]

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Learn more

• 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
• 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: per-request structured log with request-id #14165 👈 (View in Graphite)
• starknet_transaction_prover: redact URL credentials in logs and add startup banner #14164
• starknet_transaction_prover: add /health endpoint via HealthLayer #14163
• starknet_transaction_prover: add --log-format text|json CLI flag #14162
• main

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