Add wallet fingerprints

[1440000bytes]

This PR adds a wallet fingerprints panel to the transaction details page that explains the wallet-identifying patterns a transaction exhibits and gives a heuristic likely-wallet verdict.

Closes #773

Heuristics

Detection works by elimination (discard wallets whose required fingerprint is absent) adapted from ishaanam/wallet-fingerprinting, heuristic taxonomy and the set of signals follow arminsabouri/walletfingerprints.info
and arminsabouri/wallet-fingerprints-rag. Because the explorer already has the spending witness/scriptSig, input prevout types, values, and confirmation height, it covers:

• nVersion
• nLockTime / anti-fee-sniping
• RBF signaling (nSequence) and the exact nSequence value
• Input script types and multi-type vin
• Compressed vs uncompressed public keys
• Low-R grinding (compounded across the change chain)
• Signature hash type (surfaces non SIGHASH_ALL / non SIGHASH_DEFAULT flags)
• OP_RETURN outputs and output count (batching)
• BIP-69 input and output ordering
• Heuristic change detection, change-type matching, and address reuse

Signature-level checks (low-R grinding, public key compression, sighash type) read native SegWit, P2SH-nested SegWit (BIP-49), legacy P2PKH and P2PK inputs.

Testing

node app/walletFingerprintAnalysis.test.js (46 checks pass). Verified end-to-end against a regtest node and confirmed transactions render the panel with fingerprints.

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Future work

• Temporal heuristics where the data is available (RBF replacement, fee-rate source, spends-unconfirmed).
• Round-number feerate tell (arminsabouri/walletfingerprints.info).
• Canonical low-S (BIP-146) and output-script-type propensity signals.