Fix Zcash unified address validation minimum length

[coderabbitai]

Problem

The temporary hotfix in PR #748 uses a minimum length of 128 characters for Zcash unified addresses (u1 prefix). However, per ZIP-316, the actual minimum Bech32m string length for a mainnet unified address is 69 characters.

The current validation will reject all valid unified addresses between 69-127 characters in length.

Expected Behavior

Unified addresses should require a minimum of 69 characters:

• 2-char HRP + separator ("u1")
• 61 data characters (ceil(8*38/5) for 38-byte minimum payload)
• 6 checksum characters

Reference

• ZIP-316 specification: minimum decoded input is 38 bytes with HRP "u" for mainnet
• PR fix: reject short Zcash unified addresses (< 128 chars) #748: fix: reject short Zcash unified addresses (< 128 chars) #748
• Comment thread: fix: reject short Zcash unified addresses (< 128 chars) #748 (comment)
• Requested by: @jobotics

Location

src/components/DefuseSDK/utils/validateAddress.ts lines 140-143