Module modifier 

Modifier-style composable account wrappers.

Account constraints as nested type wrappers that compose at compile time. Each wrapper adds one constraint and delegates the rest to the inner type.

Signer<Mut<Account<'a, Vault>>>  -- verified signer + writable + typed overlay
Mut<Account<'a, Vault>>          -- verified writable + typed overlay
Account<'a, Vault>               -- verified owner + disc + layout_id
ReadOnly<'a, Vault>              -- foreign account, read-only

Design Principles

• Zero runtime cost: wrapper structs are transparent or ZST stacks
• Each modifier validates exactly one property
• Inner value is accessible via .inner() or Deref
• All validation happens in from_account() – if you have the type, it’s valid

Structs

Account

A typed, owner-validated account (immutable).

AccountMut

A typed, owner-validated account (mutable).

Mut

Writable wrapper – validates that the account is writable.

Signer

Signer wrapper – validates that the account is a signer.

Traits

FromAccount

Trait for types that can be constructed from an AccountView with validation.

HasView

Helper trait for types that hold an &AccountView.

HopperLayout

Trait implemented by hopper_layout! types providing layout metadata.