fix(bitcoin): validate Base58Check and Bech32/Bech32m address checksums (#21)

[meridianmindx]

Closes #21

Summary of Changes

• Base58Check Checksum Validation:
  • Implemented 4-byte checksum verification against double SHA-256 (createHash("sha256")) of the 21-byte version+payload slice for legacy (P2PKH 0x00 and P2SH 0x05) addresses.
  • Rejects single-character corruptions that alter the stored Base58 payload checksum (e.g. 14zMkTgaVXJcxdh4JdWi29MLRR44iUSG9W vs corrupted 14zMkTgaVXJcxdh4JdWi29MLRR44iUSG9X).
• Bech32 & Bech32m Polymod Verification:
  • Implemented Bech32/Bech32m polymod checksum calculation over expanded bc HRP and 5-bit data values.
  • Validates BIP-173 constant (1) for SegWit v0 (bc1q...) addresses and BIP-350 constant (0x2bc830a3) for SegWit v1+ (Taproot bc1p...) addresses.
  • Rejects single-character corruptions that fail polymod verification (e.g. bc1qaxm5p35r3yl25rdh5ex0j6wx33peht9r735x90 vs corrupted bc1qaxm5p35r3yl25rdh5ex0j6wx33peht9r735x9q).
• Automated Regression Tests:
  • Added unit test cases verifying rejection of corrupted Base58Check legacy addresses and corrupted Bech32 addresses.
  • Confirmed valid P2PKH, P2SH, Bech32 (v0 lowercase and uppercase), and Bech32m (v1 Taproot) addresses continue to pass cleanly.

Verification

• vitest run → 122/122 unit tests passing (5/5 test files).
• oxlint . → 0 errors, 0 warnings.
• oxfmt --check . → clean formatting.
• tsc --noEmit & tsc --noEmit -p tsconfig.extensions.json → clean typecheck.
• obuild → clean build output across CLI, MCP, and library entries.

Base Payout Address: 0xcFDa9f32d292661740a6d0B4c00867E34c05c56D