Accounts

An @account is a fixed layout. The first 8 bytes are sha256("account:Name"). Fields after that do not move, so Option, FixedString, and nested structs reserve their full width. Vec and data enums are rejected because a variable payload would slide later fields.

Init creates a PDA. The default seed is the snake_case account name. One literal seed replaces it (Seeds[Init[T], "vault"]). The bump is its own byte. The System program account is appended on instructions that pay or call system_transfer.

The program id is not compiled into the .so. LiteSVM assigns it when the test loads the binary. The runtime reads the id from the transaction input.