feat(openwrt): add archipelago-openwrt crate with TollGate provisioning

New `archipelago-openwrt` workspace crate provides SSH/UCI-based management
of OpenWrt routers, including automated TollGate installation and configuration
of a pay-as-you-go "archipelago" SSID backed by the local Cashu mint.

Exposes two RPC endpoints:
- `openwrt.scan` — discover OpenWrt routers on the LAN
- `openwrt.provision-tollgate` — install tollgate-module-basic-go, write UCI
  config (TIP-01/TIP-02), and create isolated WiFi SSID + firewall zone

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

core/archipelago/Cargo.toml

@@ -42,6 +42,7 @@ futures-util = "0.3"
 
 # Our modules
 archipelago-container = { path = "../container" }
+archipelago-openwrt = { path = "../openwrt" }
 archipelago-security = { path = "../security" }
 archipelago-performance = { path = "../performance" }