Bound benchmark ingestion retries and validate before transactions

[connortsui20]

Summary

Validates the commit SHA and every record before starting the ingest transaction, then retries only PostgreSQL deadlocks and serialization failures. Retries stop after eight attempts or a 120-second elapsed budget, which prevents further attempts without cancelling an active transaction.

Changes

Adds jittered backoff, connection/statement/lock timeouts, and attempt diagnostics while preserving whole-file upserts, frozen measurement IDs, and best-effort cache refresh. Adds CI coverage against the website's actual migrations, with 24 passing tests covering validation, retry bounds, real database conflicts, atomic rollback, replay, and refresh failure.

[codspeed-hq]

Merging this PR will improve performance by 24.24%

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 3 improved benchmarks
✅ 2196 untouched benchmarks
⏩ 206 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	WallTime	arrow_checked_add_u32_neon[16384]	20.4 µs	13.3 µs	+53.13%
⚡	Simulation	allocate_drop_arrow[0]	456.9 ns	402.7 ns	+13.45%
⚡	Simulation	allocate_drop_bytes[0]	575.7 ns	521.6 ns	+10.39%

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing ct/bench-writer-bounds (b1b5bfc) with develop (85b70cf)²}

Footnotes

1. 206 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on develop (5c8c397) during the generation of this report, so 85b70cf was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩