feat(clients): Wake-on-LAN in apple/linux/windows/android/decky

Each client learns a host's MAC from the mDNS `mac` TXT while it's awake, persists it on the saved-host record, and — when reconnecting to an offline host — sends a magic packet before connecting, plus an explicit "Wake host" action. Apple wraps the C-ABI; linux/windows call the core fn directly (linux also gains a --wake CLI mode); android via a new nativeWakeOnLan JNI export (the mDNS browse record gains a 7th mac field); decky shells out to the linux client's --wake before launching the stream.

iOS/tvOS need the managed com.apple.developer.networking.multicast entitlement (pending Apple approval), so the wake path + UI are gated off via PunktfunkConnection.wakeOnLANAvailable and the entitlement is commented out — keeping iOS/tvOS releasable. MAC-learning stays active on every platform so it lights up the moment it's ungated. macOS works today.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/decky/src/backend.ts

@@ -122,6 +122,12 @@ export const setSettings = callable<[settings: StreamSettings], { ok: boolean }>
   "set_settings",
 );
 export const killStream = callable<[], { ok: boolean }>("kill_stream");
+// Send a Wake-on-LAN magic packet to a saved host (headless flatpak --wake) so a sleeping host is
+// up by the time the stream connects. The MAC is looked up from the flatpak client's own
+// known-hosts store; `ok: false` (no-op) when none has been learned yet. Fire before launching.
+export const wake = callable<[host: string, port: number], { ok: boolean; error?: string }>(
+  "wake",
+);
 export const checkUpdate = callable<[force: boolean], UpdateInfo>("check_update");
 // Update the flatpak client in the user installation (`flatpak update --user -y io.unom.Punktfunk`).
 export const updateClient = callable<