feat(vault-tui): create/edit cards in the add/edit form

[UnbreakableMJ]

What

The TUI's a/e form now creates and edits card (type 3) ciphers, not just logins and secure notes. Cards were already readable in the TUI (PR #24) and writable via the CLI (PR #25) — this closes the gap so the TUI can write them too.

No backend change. It builds the CardWrite payload that already rides Request::Add/Edit.

How (crates/vault-tui/ only)

• app.rs — the Type row now cycles login → secure note → card. blank_fields/visible_fields grow the card rows (Holder / Brand / Number / Expiry / CVV; Number + CVV mask while unfocused, like Pass). submit splits the single MM/YYYY Expiry field via a local parse_expiry (mirrors the CLI's split_expiry) and packs the card fields into FormSubmit (number/code redacted in Debug). new_edit takes the cached DetailView and prefills Brand/Expiry; secrets — and the cardholder, which has no fetch selector yet — start blank = leave-unchanged.
• main.rs — submit_form builds card: Option<CardWrite> when the type is a card and threads it into both Request::Add and Request::Edit.

Tests

• card add carries split expiry + Debug-redacts the number/CVV
• card edit prefills Brand/Expiry from the detail pane and diffs only the changed expiry
• parse_expiry (both year widths + rejects garbage)
• updated type_toggle_swaps_visible_fields_preserving_values for the 3-way cycle

cargo fmt --check, fresh-isolated clippy -D warnings, cargo test --workspace --all-targets (69 TUI tests), cargo deny check, and both headless builds all clean.

Out of scope (tracked follow-ups)

• Identity TUI editing — blocked on an identity-write backend (proto IdentityWrite + from_plain identity branch + agent apply + CLI parity); that's its own slice, then identity slots into this same form.
• A Field::CardCardholder selector so the card edit form (and detail pane) can prefill/show the cardholder.

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