feat(openwrt): make TollGate payout Lightning address configurable

Archipelago never touched /etc/tollgate/identities.json — the "owner"
payout identity was whatever the router's TollGate install happened to
default to. Confirmed live against archy-x250-pa3: an unmodified upstream
placeholder (tollgate@minibits.cash), meaning 79% of every customer payment
would auto-payout to an address the operator never chose and doesn't
control.

Adds TollGateConfig.payout_address (opt-in — None leaves the router
untouched), config::apply_payout_identity() to merge it into the "owner"
entry of identities.json without disturbing the merchant keypair or the
other profit-share identities, an RPC param on openwrt.provision-tollgate,
and a status field + reconfigure-form input in the OpenWrt Gateway panel.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KTdMfVJChCwCCYF1ZTRQLc

core/openwrt/src/tollgate/mod.rs

@@ -68,6 +68,8 @@ pub async fn provision(router: &Router, config: &TollGateConfig) -> Result<()> {
     // the daemon restart below — config.json is only read at startup.
     config::apply_daemon_config(router, config)
         .context("write /etc/tollgate/config.json — tollgate-wrt reads this, not UCI")?;
+    config::apply_payout_identity(router, config.payout_address.as_deref())
+        .context("write /etc/tollgate/identities.json owner payout address")?;
     // Also must come after provision_ssid: points gatewayinterface at
     // br-tollgate, which provision_ssid is what creates.
     nodogsplash::configure(router, config)