feat(cli): invoice return — bulk + nametag (depends on sphere-sdk #405)

[vrogojin]

Summary

Adds three input shapes for sphere invoice return:

sphere invoice return <id>                              # refund every sender (NEW)
sphere invoice return <id> --recipient @alice           # refund all balances owed to @alice (NEW)
sphere invoice return <id> --recipient @alice --asset 3 UCT  # refund exactly (existing, with nametag resolution)

The first two delegate to sphere-sdk PR #405's new AccountingModule.returnAllInvoicePayments(invoiceId, options?). That SDK method iterates getInvoiceStatus().senderBalances and refunds every attributed payment to its recorded sender — so operators don't have to fish per-send DIRECT://… addresses out of invoice status JSON. Particularly important for masked-predicate sends (the privacy default), where the on-chain sender is a one-time DIRECT://… the user cannot guess from their wallet's identity.

The third (explicit) shape also gains @nametag resolution for --recipient — same as invoice deliver --to and invoice create --target. Previously --recipient was passed verbatim to the SDK, so @alice would break with Return amount X exceeds sender net balance 0 (the SDK did a literal-string lookup against the recorded DIRECT://…).

Output shape

Form A (single explicit refund) — single-row:

Return payment result:
  id     : <transferId>
  status : submitted
  recipient : DIRECT://…
  amount    : 3 UCT

Forms B/C (bulk) — multi-row:

Return payment results:
  2 refund(s) submitted:
  [0] 3 UCT → DIRECT://0000abcd…
       id     : <transferId>
       status : submitted
  [1] 4 UCT → DIRECT://0000efgh…
       id     : <transferId>
       status : submitted

The renderer auto-detects via Array.isArray(p.refunds). Both shapes available under --json.

Dependencies

• sphere-sdk PR #405 (feat/accounting-return-all-invoice-payments) — adds AccountingModule.returnAllInvoicePayments. This PR's forms B and C call it.

This PR is the CLI surface that exposes #405's primitive.

Verification

• npx tsc --noEmit — clean
• npx vitest run — 126/126 pass (UX static-guard now green)
• npx tsup — ESM + CJS + DTS build clean
• sphere invoice return --help — shows all 3 forms with examples + notes block

Live testnet end-to-end exercise of form C (no flags) in the new accounting soak (sphere-sdk PR #406): bob's bulk-refund correctly drains 3 UCT and credits alice's wallet. The token-level flow is exact.

(There's a separate sphere-sdk attribution bug #404 that prevents the SDK's invoice ledger from reflecting masked-predicate refunds — that's documented as a follow-up; it doesn't block this PR since the bug is upstream of the CLI wrapper.)

Out of scope

• --asset without --recipient is rejected with a clear error pointing to either form. Refunding a specific amount without specifying the recipient is ambiguous.
• --asset-index / --target-index selectors stay unimplemented — single-asset single-target invoices are the only shape exercised today.

Related

• sphere-cli fix(cli)(#36): invoice pay --amount accepts human units #37 (fix/issue-36-invoice-pay-human-units) — partner PR for the human-unit --amount on invoice pay. The accounting soak exercises both.
• sphere-cli fix(cli): bare-namespace help for invoice / swap / group / market #38 (fix/sphere-namespace-bare-help) — partner PR for sphere invoice (no sub) help.
• sphere-sdk #405 — the dependency.
• sphere-sdk #406 — the soak that exercises this end-to-end.
• sphere-sdk #404 — known SDK attribution bug (workaround in #406's §13).