feat(wallet): Ark protocol support via barkd sidecar

barkd (Ark wallet daemon, pinned 0.3.0, checksum-verified release binary)
packaged as an installable app; thin HTTP bridge in wallet/ark_client.rs
mirrors the fedimint_client pattern — the bark SDK stays out of the node
binary. wallet.ark-* RPCs cover status/balance/address/send/invoice/
board/offboard/history/configure; Ark movements merge into the unified
ecash history (kind="ark") and spendable Ark sats into total_sats.
Signet defaults (Second's public Ark server) until Ark matures.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

core/archipelago/src/container/docker_packages.rs

@@ -372,6 +372,13 @@ fn get_app_metadata(app_id: &str) -> AppMetadata {
             repo: "https://github.com/minmoto/fmcd".to_string(),
             tier: "",
         },
+        "barkd" | "bark" => AppMetadata {
+            title: "Ark Wallet".to_string(),
+            description: "Ark protocol wallet daemon (barkd) — self-custodial off-chain bitcoin via an Ark server (signet)".to_string(),
+            icon: "/assets/img/app-icons/bark.png".to_string(),
+            repo: "https://gitlab.com/ark-bitcoin/bark".to_string(),
+            tier: "",
+        },
         "morphos" | "morphos-server" => AppMetadata {
             title: "Morphos".to_string(),
             description: "Self-hosted file converter".to_string(),