feat(wallet): WalletTx now supports non-canonical txs

[noahjoeris]

Description

WalletTx was an alias for CanonicalTx, so wallet.transactions() and wallet.get_tx(txid) only returned canonical wallet-relevant txs. Evicted/replaced txs disappeared tho still wallet relevant.

This PR changes WalletTx to TransactionInfo and makes it a struct that represents any wallet-relevant tx:

/// A wallet-relevant transaction and its metadata.
pub struct TransactionInfo<'a> {
    /// Wallet-specific amounts, fees, and canonicality.
    pub details: TxDetails,
    /// Graph metadata such as anchors, first_seen, and last_seen.
    pub tx_node: TxNode<'a, Arc<Transaction>, ConfirmationBlockTime>,
    /// Latest backend observation that this tx was absent from the mempool.
    pub last_evicted: Option<u64>,
    /// Direct conflicts spending the same inputs.
    pub conflicts: Vec<Txid>,
}

/// The canonicality of a wallet-relevant transaction.
pub enum TxCanonicality {
    /// The transaction is currently canonical.
    Canonical(ChainPosition<ConfirmationBlockTime>),
    /// The transaction is currently not canonical.
    NonCanonical,
}

Canonical status lives in details.canonicality.

Fixes #295

Supported use cases

• Keep dropped txs visible in wallet history.
• Show whether an evicted tx has conflicts.
• Let users decide when it is safe to forget an old dropped tx.
• Give users enough information to warn before accidentally paying twice.

Surface now including non-canonical txs

• TransactionInfo, TxCanonicality, TxDetails, transactions(), get_tx()

Notes to the reviewers

• Performance of transactions() takes a small hit. Worth confirming whether it's an issue in practice.
• Still need to add tests.

Changelog notice

• Changed: WalletTx → TransactionInfo struct with details, tx_node, last_evicted, conflicts; WalletTxStatus → TxCanonicality.
• Changed: transactions() / get_tx() also return non-canonical wallet-relevant txs.
• Changed: TxDetails::chain_position → canonicality.
• Removed: Wallet::tx_details(txid), use wallet.get_tx(txid).details.

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran just p before pushing

New Features:

• I've added tests for the new feature
• I've added docs for the new feature
• This pull request breaks the existing API

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.52%. Comparing base (4b612f5) to head (cd09dc5).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #480      +/-   ##
==========================================
+ Coverage   80.30%   80.52%   +0.21%     
==========================================
  Files          24       24              
  Lines        5417     5478      +61     
  Branches      245      246       +1     
==========================================
+ Hits         4350     4411      +61     
  Misses        989      989              
  Partials       78       78              

Flag	Coverage Δ
rust	80.52% <100.00%> (+0.21%)	⬆️

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[aagbotemi]

nit: the is_canonical(t) filter above only allows canonical txids into blockers, and txid is non-canonical here, so this line is unreachable. So, I think it's safe to remove.

[ValuedMammal]

Concept ACK

[noahjoeris]

After some ideas by ValuedMammal I simplified the model a bit:

• Renamed WalletTx → TransactionInfo, WalletTxStatus → TxCanonicality.
• Replaced canonical_blockers() with a direct-only conflicts: Vec<Txid> field; moved last_evicted to a top-level field on TransactionInfo.

PR description updated accordingly.