feat: Bark expansion

[orangeshyguy21]

New Features

• Configurable Bark payment methods — cdk-bark-processor gains payment_methods (bolt11, onchain, arkoor); the default advertises all three, as upstream does.
• On-chain and arkoor on CDK mints — CDK 0.18.1 mints can bind on-chain and arkoor to the Bark processor, alone or beside embedded BDK.
• Per-backend mint units — each CDK payment section takes its unit from its links, or from the new embedded_lightning_unit for LDK Node.

Changes

• Bark mints bind every advertised method — a mint must bind each method its Bark processor advertises, exactly once.

Important

Existing Bark cells with only a bolt11 binding no longer validate. Add onchain and arkoor bindings, or set payment_methods: ["bolt11"] on the processor. Recreate affected cells.

• CDK limit fields renamed — min_mint_sat, max_mint_sat, min_melt_sat and max_melt_sat are now min_mint, max_mint, min_melt and max_melt.

Important

Update authored CDK mint configs to the new names. On-chain (onchain_*_sat) and Nutshell limits are unchanged.

• Open payment methods and units — methods and units are now open Cashu strings, so custom values like arkoor need no code change.
• Stricter processor readiness — GetSettings must report exactly the configured methods, and startup refuses a missing method list.
• Embedded backends checked at lock time — embedded LDK Node and BDK payment tuples must be listed in the catalog.
• Version — bumped to 0.1.0-alpha.9.

Note

The catalog still admits only sat. msat for LND, CLN and LDK Node needs its own qualification gate first.

Testing

• Managed Bark gate — now checks exact method registration on processor and mint, and credits an on-chain deposit boarded into Ark.
• Unit and golden coverage — topology, rendering, driver handshake and lock-time unit checks; format, clippy and workspace tests pass locally.

Note

The new Bark gate stages run for the first time in this PR's CI. arkoor payments and on-chain melts are not exercised.