Improve multisig UX: Add --out-file parameter and enhance sign-tx

[ladamesny]

Description

Improves the multisig workflow by eliminating the need for manual jq extraction of transaction CBOR hex. Adds an optional --out-file parameter to governed-map commands and enhances sign-tx to accept multiple input formats.

Changes

1. Added --out-file to governed-map commands

• New optional parameter for insert, update, and remove commands
• Automatically extracts and saves cborHex to the specified file during multisig flows
• Prints success message to stderr when file is written
• Returns explicit error if --out-file specified but cborHex unavailable

2. Enhanced sign-tx input handling

• Now accepts three input formats:
  • Direct hex string (existing behavior)
  • Full transaction_to_sign JSON string
  • Path to JSON file containing transaction data
• Added extract_cbor_hex() with deterministic parsing order (file → JSON → hex)
• Improved help text to clarify accepted formats

3. Code quality improvements

• Uses PathBuf instead of String for file paths (type safety)
• Added clap::ValueHint::FilePath for better shell autocompletion
• Better error messages and user feedback

Example Usage

# Save transaction CBOR to file
./partner-chains-node smart-contracts governed-map insert \
  --genesis-utxo <UTXO> \
  --ogmios-url ws://localhost:1337 \
  --payment-key-file key.skey \
  --key "my-key" \
  --value 0x1234 \
  --out-file tx.cbor

# Sign using the saved file directly
./partner-chains-node smart-contracts sign-tx \
  --transaction tx.cbor \
  --payment-key-file key.skey

Checklist

• Commit sequence broadly makes sense and commits have useful messages.
• The size limit of 400 LOC isn't needlessly exceeded
• The PR refers to a JIRA ticket (if one exists)
• New tests are added if needed and existing tests are updated.
• New code is documented and existing documentation is updated.
• Relevant logging and metrics added
• Any changes are noted in the changelog.md for affected crate
• Self-reviewed the diff

[LGLO]

You have tx_data.tx that are bytes. Then you serialized it Cardano file JSON and then you take this field containing bytes of the transaction instead of using it directly.

You could just hex::encode(tx_data.tx), couldn't you?

[LGLO]

A this point I would parse MultiSigTransactionData instead of manually traversing its format