feat(desktop): bake local Laptop relay into default relay list for testing

Adds 172.16.81.125:4433 (the laptop's LAN IP) as the first default relay
so the Android rewrite can be tested against a relay whose logs are on the
same host as the builds and screenshots. On fresh installs the Laptop
relay is pre-selected as index 0. On upgrades from an older cached
settings blob, a one-shot migration unshifts it to the front if missing,
so we don't have to tap through Manage Relays after every reinstall.

Marked "remove once Android rewrite is stable" — the address is a hardcoded
LAN IP that won't be valid in other environments.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

desktop/src/main.ts

@@ -109,7 +109,12 @@ interface Settings {
 
 function loadSettings(): Settings {
   const defaults: Settings = {
-    relays: [{ name: "Default", address: "193.180.213.68:4433" }],
+    relays: [
+      // Local laptop relay — used during Android rewrite testing so the phone
+      // and the relay logs are on the same host. Laptop IP on the test LAN.
+      { name: "Laptop", address: "172.16.81.125:4433" },
+      { name: "Default", address: "193.180.213.68:4433" },
+    ],
     selectedRelay: 0, room: "android", alias: "",
     osAec: true, agc: true, quality: "auto", recentRooms: [],
   };
@@ -126,6 +131,15 @@ function loadSettings(): Settings {
         const addr = parsed.relays?.[0]?.address || defaults.relays[0].address;
         parsed.recentRooms = parsed.recentRooms.map((r: string) => ({ relay: addr, room: r }));
       }
+      // Ensure the Laptop test relay is present as the first entry for
+      // existing installs — otherwise users with cached settings keep using
+      // the remote default and we have to manually add it each install.
+      // Remove this block once the Android rewrite is stable.
+      const LAPTOP_ADDR = "172.16.81.125:4433";
+      if (Array.isArray(parsed.relays) && !parsed.relays.some((r: any) => r.address === LAPTOP_ADDR)) {
+        parsed.relays.unshift({ name: "Laptop", address: LAPTOP_ADDR });
+        parsed.selectedRelay = 0;
+      }
       return { ...defaults, ...parsed };
     }
   } catch {}