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/android/native/src/wol.rs

@@ -0,0 +1,40 @@
+//! JNI seam for Wake-on-LAN: parse the stored MAC strings and hand them to the shared core sender
+//! (`punktfunk_core::wol`). Like [`crate::discovery`], this takes no session handle — a sleeping
+//! host has no ARP entry, so the broadcast the core sends is what wakes it, and Kotlin calls this
+//! just before connecting to an offline saved host.
+
+use jni::objects::{JObject, JString};
+use jni::JNIEnv;
+
+/// `NativeBridge.nativeWakeOnLan(macsCsv: String, lastIp: String): Boolean` — send a Wake-on-LAN
+/// magic packet. `macsCsv` is comma-separated MACs (`aa:bb:..,cc:dd:..`, learned from the host's
+/// mDNS `mac` TXT while it was online); `lastIp` is the host's last-known IPv4 (or empty).
+/// Returns true if at least one datagram went out.
+#[no_mangle]
+pub extern "system" fn Java_io_unom_punktfunk_kit_NativeBridge_nativeWakeOnLan<'local>(
+    mut env: JNIEnv<'local>,
+    _this: JObject<'local>,
+    macs_csv: JString<'local>,
+    last_ip: JString<'local>,
+) -> jni::sys::jboolean {
+    let macs_csv: String = match env.get_string(&macs_csv) {
+        Ok(s) => s.into(),
+        Err(_) => return 0,
+    };
+    let last_ip: String = env
+        .get_string(&last_ip)
+        .map(|s| Into::<String>::into(s))
+        .unwrap_or_default();
+    let macs: Vec<[u8; 6]> = macs_csv
+        .split(',')
+        .filter_map(|s| punktfunk_core::wol::parse_mac(s.trim()))
+        .collect();
+    if macs.is_empty() {
+        return 0;
+    }
+    let ip = last_ip.trim().parse::<std::net::Ipv4Addr>().ok();
+    match punktfunk_core::wol::send_magic_packet(&macs, ip) {
+        Ok(()) => 1,
+        Err(_) => 0,
+    }
+}