[olga24912]

Fixes for the QA / Informational findings from the audit.

• QA-02: the user's withdrawal output must now equal amount - withdraw_fee - gas_fee exactly; the min_change_amount relaxation is removed, so no unaccounted nBTC remainder is left on the bridge.
• QA-03: release workflows hardened:
  actions are pinned to commit SHAs;
  cargo-near is pinned to a specific version and its SHA-256 is verified;
  build (contents: read) and publish (contents: write) run as separate jobs;
  releases now include checksums.sha256.
• QA-04: assert_valid requires min_deposit_amount > deposit_bridge_fee.fee_min; documented the zero values of rbf_num_limit and the refund timelocks.
• QA-06: new Zcash-only view list_btc_pending_expiry_heights exposes the expiry height of pending transactions.
• QA-08: set_withdraw_relayer_address in nBTC now requires one yocto.
• QA-10: updated CLAUDE.md, doc/refund-flow.md and the verify_deposit_v2 doc comment to match the current entrypoints, the withdraw flow, the safe-deposit callback semantics and the refund permissions.

[karim-en]

why do we need this?

[olga24912]

I was unsure whether to add this method or not, but in the end I decided to add it.

It's needed in case a transaction gets stuck and doesn't even submitted it into the mempool — this way it will be easiest to check its expiry_height. Otherwise, we would have to parse the transaction.

I don't have a strong opinion about this method.

[karim-en]

is this correct?

[olga24912]

Yes, and I think it's fairer to the user this way.

[github-actions]

WASM size

Contract	Size	Base	Δ	Δ %
bitcoin	1230.2 KiB	1255.9 KiB	-25.7 KiB	-2.05%
zcash	1347.4 KiB	1369.7 KiB	-22.4 KiB	-1.63%

Fails above +2% growth (ignoring deltas under 1024 bytes).

_{aecb805 vs base 1cf39b1 · run}