Variable DEFAULT_COMPRESSIBLE_CONFIGConst

Default compressible config for light-token ATAs - matches Rust SDK defaults.

• tokenAccountVersion: 3 (ShaFlat) - latest hashing scheme
• rentPayment: 16 - prepay 16 epochs (~24 hours rent)
• compressionOnly: 1 - required for ATAs
• writeTopUp: 766 - per-write top-up (~2 epochs rent) when rent < 2 epochs
• compressToAccountPubkey: null - required for ATAs

Cost breakdown at associated token account creation:

• Rent sponsor PDA (LIGHT_TOKEN_RENT_SPONSOR) pays: rent exemption (~890,880 lamports)
• Fee payer pays: compression_cost (11K) + 16 epochs rent (~6,400) = ~17,400 lamports + tx fees

Per-write top-up (transfers):

• When account rent is below 2 epochs, fee payer pays 766 lamports top-up
• This keeps the account perpetually funded when actively used

Rent calculation (272-byte compressible ctoken account):

• rent_per_epoch = base_rent (128) + bytes * rent_per_byte (272 * 1) = 400 lamports
• 16 epochs = 16 * 400 = 6,400 lamports (24 hours)
• 2 epochs = 2 * 400 = 800 lamports (~3 hours, writeTopUp = 766 is conservative)

Account size breakdown (272 bytes):

• 165 bytes: SPL token base layout
• 1 byte: account_type discriminator
• 1 byte: Option discriminator for extensions
• 4 bytes: Vec length prefix
• 1 byte: extension type discriminant
• 4 bytes: CompressibleExtension header (decimals_option, decimals, compression_only, is_ata)
• 96 bytes: CompressionInfo struct