feat: atas & other well known programs

[amilz]

• Auto-inject well-known programs: New SetWellKnownProgramsVisitor runs automatically in DefaultPlugin.on_root_node_set() after CombineModulesVisitor. Scans the final RootNode for ProgramLinkNode references in instruction default values and injects matching well-known programs into additional_programs if not already present. Zero config — no extra plugin, no boilerplate struct.
• ata() shorthand directive: Simple handler for associated token PDA default values. Takes 3 positional seed values and hardcodes the fixed seed names (owner, tokenProgram, mint) and program link automatically.
• Well-known registry: associatedToken, system, token, token2022, memo — with addresses and PDAs. Easy to extend.

Before / After

// BEFORE: 11 lines of boilerplate struct + verbose pda() syntax

#[derive(CodamaPda)]
#[codama(program(name = "associatedToken", address = "ATokenGPvbdGVxr1b2hvZbsiqW5xWH25efTNsLJA8knL"))]
#[codama(seed(name = "owner", type = public_key))]
#[codama(seed(name = "tokenProgram", type = public_key))]
#[codama(seed(name = "mint", type = public_key))]
pub struct AssociatedToken;

// ... in instruction:
#[codama(account(
    name = "vault",
    writable,
    default_value = pda("associatedToken", program = "associatedToken", [
        seed("owner", account("escrow")),
        seed("tokenProgram", account("tokenProgram")),
        seed("mint", account("mint"))
    ])
))]

// AFTER: just this

#[codama(account(
    name = "vault",
    writable,
    default_value = ata(account("escrow"), account("tokenProgram"), account("mint"))
))]

The pda(...) syntax still works if you need full control:

#[codama(account(
    name = "vault",
    writable,
    default_value = pda(
        "associatedToken",
        program = "myCustomAtaProgram",
        [
            seed("owner", account("escrow")),
            seed("tokenProgram", account("tokenProgram")),
            seed("mint", account("mint"))
        ]
    )
))]

Design decisions

• Opted for integrating directly into DefaultPlugin rather than a standalone plugin since ATA is ubiquitous in Solana programs — adding a separate add_plugin() call for something almost everyone needs would defeat the zero-config goal.
• ata() takes positional seed values (not named seeds) — the seed names are always owner/tokenProgram/mint for an ATA, so the shorthand hardcodes them.
• The visitor runs after CombineModulesVisitor so it sees the fully assembled tree. It only injects programs that are (a) referenced and (b) not already present.
• No program override on ata() — if you need a custom ATA-like program, use pda() directly. Keeps the shorthand opinionated and simple (I've never once seen anyone override ATA program).
• The well-known registry also covers programs referenced via default_value = program("system") etc. — if a ProgramLinkNode reference exists but the program isn't in the tree, the visitor injects it with the correct address.

Test plan

• cargo test -p codama-korok-visitors — 15 integration tests in tests/set_well_known_programs_visitor.rs (injection of each program, deduplication, unknown refs ignored, sub-instruction traversal, multiple programs, argument/extra_argument collection, additional programs)
• cargo test -p codama-attributes — 8 inline unit tests for ata parser (positional seeds, different account names, argument seeds, mixed types, error cases)
• cargo test -p codama-korok-plugins — plugin integration
• Verified end-to-end against escrow program — IDL output matches expected format with auto-injected associatedToken program

LMK what you think @lorisleiva

[amilz]

replaced with #84

[lorisleiva]

@amilz I can find some time next week to create that TokenPlugin now that the architecture is ready for it. ☺️