Leios prototype tx-firehose: dynamically allow for txs with more outputs

[ch1bo]

Two bugs stopped --outputs-per-tx > 1 from running for more than a few seconds, both showing up as "insufficient funds - total inputs (364400 lovelace) do not cover fee (1000000)".

takeInputs picks by TxIn order, i.e. effectively at random, so it could select target dust entries and split their sum target ways — producing finer dust, and repeating. 364,400 lovelace sits exactly in the divide-by-5 sequence down from the original 30M ADA, with the value itself untouched (29,999,924,000,000 across 305 UTxOs) simply because it was never selected. takeLargest instead takes the target largest funds, extending with the next largest until they cover fee + target * outputFloor, so an output is never created too small to spend again and stranded dust gets consolidated rather than sharpened. That also subsumes the fan-out case, so takeFattest goes.

Separately, keeping the inputs on a reject is right for a transient failure but wrong when the ledger says they are gone: takeInputs is deterministic, so the retry rebuilt the same tx and earned the same rejection until max-consecutive-errors. Worse at startup with a single UTxO and a fan-out target, where that one tx is the only one buildable.

Measured on dozen-devnet: --outputs-per-tx 5 gives 648 B transactions, 5 in / 5 out, no failures.

Description

Add your description here, if it fixes a particular issue please provide a
link
to the issue.

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. These may include:
  • golden tests
  • property tests
  • roundtrip tests
  • integration tests
    See Running tests for more details
• Any changes are noted in the CHANGELOG.md for affected package
  • cardano-node-chairman, cardano-submit-api and cardano-testnet instead need a
    changelog fragment in <package>/.changes/, because their CHANGELOG.md is generated
    from fragments at release time. Copy _TEMPLATE.yml from that directory, or run
    nix run github:input-output-hk/cardano-dev#herald -- new
• The version bounds in .cabal files are updated
• CI passes. See note on CI. The following CI checks are required:
  • Code is linted with hlint. See .github/workflows/check-hlint.yml to get the hlint version
  • Code is formatted with stylish-haskell. See .github/workflows/stylish-haskell.yml to get the stylish-haskell version
  • Code builds on Linux, MacOS and Windows for ghc-9.6 and ghc-9.12
• Self-reviewed the diff

Note on CI

If your PR is from a fork, the necessary CI jobs won't trigger automatically for security reasons.
You will need to get someone with write privileges. Please contact IOG node developers to do this
for you.