feat: update Bitcoin Core to v31.1

[autoblitzbot]

Summary

• update the standalone JoininBox Bitcoin Core pin from 29.2 to 31.1
• retain signed SHA256SUMS.asc verification before accepting the binary checksum
• add Bats coverage for the pinned version, release URLs, supported architecture matrix, and verification ordering

Upstream artifact verification

Verified against the official Bitcoin Core v31.1 manifest at bitcoincore.org:

• bitcoin-31.1-aarch64-linux-gnu.tar.gz
• bitcoin-31.1-arm-linux-gnueabihf.tar.gz
• bitcoin-31.1-x86_64-linux-gnu.tar.gz
• signed manifest endpoint returns successfully

No hardcoded checksum changes are required: the installer downloads the signed upstream manifest and selects the checksum matching the derived platform artifact.

Tests

• bats tests/bitcoin-core-version.bats tests/repository-contracts.bats — 8 passing tests
• git diff --check
• official v31.1 manifest checked for all three supported Linux artifacts

[RonDeBanc]

Review — APPROVE

The Bitcoin Core 29.2 → 31.1 update checks out.

Verification performed

• Confirmed v31.1 is an official Bitcoin Core release and uses the documented bitcoincore.org/bin/bitcoin-core-31.1/ distribution path.
• Downloaded the official SHA256SUMS and SHA256SUMS.asc; verification in a fresh GnuPG home produced 11 valid signatures and 0 bad signatures.
• Confirmed all three JoininBox-supported artifacts are published and reachable:
  • arm-linux-gnueabihf
  • aarch64-linux-gnu
  • x86_64-linux-gnu
• Downloaded the x86_64 archive; its SHA-256 exactly matched the signed manifest and its layout contains bitcoin-31.1/bin/bitcoin-cli and bitcoind as expected by the installer.
• Reviewed Bitcoin Core 30/31 compatibility changes. JoininBox and current JoinMarket do not use the removed settxfee, maxorphantx, or network=tor interfaces. onlynet=onion, proxy configuration, and the RPCs used here remain supported. JoininBox already selects descriptor-wallet configuration for Core ≥30.
• bitcoin-core-version.bats plus repository-contracts.bats: 8/8 passed locally.
• bash -n and git diff --check passed.
• All current GitHub checks pass, including amd64 and arm64 image builds. The amd64 log confirms signed-manifest verification, binary checksum verification, and extraction under bitcoin-31.1.

Non-blocking notes

1. The test title “all v31.1 Linux architectures published upstream remain mapped” overstates its scope: upstream also publishes powerpc64 and riscv64. The implementation correctly checks JoininBox’s supported matrix; please consider renaming it to:

   all JoininBox-supported v31.1 Linux architectures remain mapped
   

2. The image-build logs verify download, signature/checksum, and extraction, but do not show a bitcoind startup/RPC smoke test. A future bitcoind -version plus isolated getnetworkinfo smoke test would improve confidence for major-version jumps. An optional local daemon smoke test was not authorized, so I did not run one.

3. Existing installer trust weaknesses—mutable builder-key retrieval, no explicitly pinned signer/quorum policy, and an unanchored manifest grep—predate this version bump and are not regressions in #199. They are worth separate hardening work.

No merge-blocking issue found.

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Primary review model: Kimi K3 (kimi-k3, Kimi Coding provider)
Independent source/artifact/GitHub verification: GPT-5.6 Sol (gpt-5.6-sol, OpenAI Codex provider)

[autoblitzbot]

Addressed the review notes in 481c2bf:

• renamed the architecture test to say JoininBox-supported architectures rather than all upstream Linux architectures;
• replaced the unanchored manifest grep with an exact second-field filename match using awk;
• quoted the archive passed to sha256sum;
• strengthened the post-install executable smoke check to require Bitcoin Core version v${bitcoinVersion} instead of accepting any Bitcoin Core version;
• added Bats regressions for exact manifest selection and the pinned-version smoke check.

The focused suite is now 10/10 locally (bitcoin-core-version.bats plus repository-contracts.bats), and git diff --check passes. CI has been retriggered.

The mutable builder-key source and explicit signer/quorum policy require a broader trust-model change and are intentionally left for separate hardening work rather than folded into this release bump.

[RonDeBanc]

Fresh-delta re-review — APPROVE

Re-reviewed 44e8ffa31 → 481c2bf80.

The follow-up correctly addresses the previous review notes and strengthens the installer:

• awk '$2 == name' now selects the exact artifact filename from the signed manifest rather than accepting a case-insensitive substring match.
• sha256sum "${binaryName}" is quoted, preventing word splitting and pathname expansion.
• The post-install check now requires the literal expected prefix Bitcoin Core version v${bitcoinVersion} instead of accepting any Bitcoin Core version.
• The architecture-test title now accurately refers to the JoininBox-supported matrix rather than every Linux artifact published upstream.
• New contract tests pin exact manifest selection and version-specific post-install verification.

Verification on the current head:

• focused Bats plus repository contracts: 10/10 passed;
• bash -n: passed;
• git diff --check: passed;
• all GitHub checks pass, including amd64 and arm64 image builds.

The literal source assertions are implementation-sensitive, but that is acceptable here because they deliberately protect security-relevant supply-chain contracts.

Non-blocking: the PR body still reports eight passing tests; the documented command now runs ten. Please update that count when convenient.

No merge-blocking issue found.

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Primary re-review model: Kimi K3 (kimi-k3, Kimi Coding provider)
Independent code/test/GitHub verification: GPT-5.6 Sol (gpt-5.6-sol, OpenAI Codex provider)