Record that the local-network permission survives the tunnel

Android's Local Network Definition says a local network "excludes
cellular (WWAN) or VPN connections", which reads as: an app reaching its
server through WireGuard needs no ACCESS_LOCAL_NETWORK. Both projects
reach their server through WireGuard, so both had a reason to delete it.

Measured on a real device on 2026-08-28: the permission is still
required, and without it the traffic is dropped. The documented exclusion
does not hold for a tun carrying an RFC1918 destination.

The note goes here because this is the one function a person would read
before removing the permission, and because neither project can find this
out for itself -- the API 36 emulator images both are tested against do
not enforce the permission at all, so removing it passes every test
available locally and fails only on the phone.

app/src/main/kotlin/com/example/wgapplink/ServerConfig.kt

@@ -147,6 +147,18 @@ class ServerStore(private val scheme: String, private val keyAlias: String) {
  * the OS drops the traffic, so a blocked app and an unreachable server produce the same connect
  * timeout. Without asking explicitly there is no way to tell those apart, and the failure shown
  * would blame the server or the tunnel for something neither is doing.
+ *
+ * **The permission is still required when the server is reached through WireGuard, and the
+ * platform's own documentation says otherwise.** Android's Local Network Definition describes a
+ * local network as one that "utilizes a broadcast-capable network interface, such as Wi-Fi or
+ * Ethernet, but excludes cellular (WWAN) or VPN connections" — read straight, a tunnelled 10.66.0.1
+ * is excluded and needs nothing. Measured on a real device on 2026-08-28: it is not excluded, and
+ * without the permission the traffic is dropped. Do not remove the permission on the strength of
+ * that paragraph.
+ *
+ * **Neither project can catch this in an emulator.** The API 36 images both are tested against do
+ * not enforce the permission at all, so removing it passes every local test and fails only on a
+ * phone. That asymmetry is the reason this note is here rather than in a commit message.
  */
 fun localNetworkAllowed(context: Context): Boolean =
     android.os.Build.VERSION.SDK_INT < 37 ||