Add `appeal` CLI command

[Levi-Ojukwu]

Description:

The CLI has commands for submitting, funding, canceling, and paying invoices, but no command to file an appeal against a defaulted invoice. The appeal_default contract function allows a payer to contest an unfair default ruling within 30 days.

The CLI command should:

• Accept --invoice-id (required) — the invoice to appeal
• Accept --evidence-hash (required) — SHA-256 hash of off-chain evidence
• Accept --payer (optional) — payer address (defaults to configured wallet)
• Call the contract's appeal_default function
• Display the transaction result

The command should follow the pattern established by existing commands like cli/src/commands/submit.ts.

Why it matters: Payers need a simple way to file appeals without writing code. The CLI is the primary interface for non-developer users.

Acceptance Criteria:

• Create cli/src/commands/appeal.ts following the pattern of submit.ts
• Accept --invoice-id and --evidence-hash parameters
• Validate that the invoice exists and is in Defaulted status
• Register the command in cli/src/index.ts as iln appeal
• Add tests in cli/tests/

Relevant Files: cli/src/index.ts, cli/src/commands/submit.ts (pattern reference), contracts/invoice_liquidity/src/lib.rs (appeal functions)

---

[nazteeemba]

Please assign me to this issue

[prissca]

i will love to work on this issue, i have gone through the requirement and i understood it

[grantfox-oss]

🦊 GrantFox — @prissca has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #413)
2. Your PR will be reviewed by the Invoice-Liquidity-Network maintainers

Good luck! Track your progress on GrantFox.