feat(solana): add Marinade Finance visualizer preset

[kyle-anchorage]

1. Why this PR exists

Solana stake-pool transactions to Marinade Finance (program MarBmsSgKXdrN1egZf5sqe1TMai9K1rChYNDJgjq7aD) fell through to the unknown-program catch-all visualizer. Signers saw raw instruction bytes instead of a human-readable instruction name, decoded arguments, and named accounts.

No ticket.

2. What changed

• Adds a new Solana preset marinade_finance under chain_parsers/visualsign-solana/src/presets/, scaffolded from the program's on-chain Anchor IDL (bundled as marinade_finance.json via include_str!).
• MarinadeFinanceVisualizer decodes each instruction by its 8-byte discriminator using the shared parse_instruction_with_idl path, then renders a preview layout: condensed view (program + instruction name) and expanded view (program id, instruction, discriminator, IDL-named accounts, and decoded args, all alphabetically sorted), with a raw-data field appended.
• Falls back to a "IDL parsing failed - showing raw data" view when the discriminator is unknown or data is shorter than 8 bytes, so unrecognized instructions still degrade gracefully instead of erroring.
• config.rs registers the program with a wildcard ("*", ["*"]) instruction allow-list.
• No edits to presets/mod.rs or the visualizer registry: both are auto-generated by build.rs from the directory listing, so the preset is wired in purely by the directory drop-in (struct name MarinadeFinanceVisualizer matches the pascal-cased directory name).

3. Why this is safe

• Backward compatibility: purely additive. Before this change, Marinade transactions matched the unknown_program catch-all; the catch-all still runs last (build.rs partitions it after all specific visualizers), so only Marinade-program instructions are newly claimed. No existing preset behavior changes.
• How it was built: decoding reuses the existing solana_parser IDL machinery (decode_idl_data, parse_instruction_with_idl) already used by other presets. The IDL is parsed once and cached in a OnceLock. Field construction uses the mandated create_text_field / create_raw_data_field builders.
• Risks mitigated: instruction data shorter than the 8-byte discriminator and unknown discriminators both return errors that route to the fallback view rather than panicking. No unwrap/expect/panic in non-test code, satisfying the workspace lint policy.

Checks run (by agent)

• cargo test -p visualsign-solana marinade — 4 tests pass (IDL loads, all discriminators are 8 bytes, unknown discriminator errors, short data errors).
• cargo clippy -p visualsign-solana --all-targets -- -D warnings — clean.

Manual steps needed (by human)

None — fully automated by CI.

4. How this is maintainable

• The preset follows the established directory-drop-in convention documented in presets/mod.rs and enforced by build.rs; a fresh developer adds a chain integration by creating a presets/<name>/ directory with a <Name>Visualizer, no registry edits.
• The bundled IDL is the source of truth for instruction names, discriminators, and account ordering, so the visualizer tracks the on-chain program without hand-maintained tables.
• Tests guard the IDL contract (non-empty, 8-byte discriminators) and the error paths, catching regressions if the bundled IDL is replaced or the parser changes.
• Mirrors the structure of sibling presets (e.g. kamino_vault, orca_whirlpool), so patterns are consistent across the crate.

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