refactor(client): extract UI-agnostic plumbing into pf-client-core (phase 0)

Session pump, FFmpeg decode, PipeWire audio, SDL3 gamepads, keymap, trust
store, mDNS discovery, library client and Wake-on-LAN move verbatim from
clients/linux into crates/pf-client-core, shared with the upcoming Vulkan
session binary (punktfunk-planning: linux-client-rearchitecture.md).
The GTK client re-exports them at the crate root so every existing
crate::-path keeps resolving; its manifest drops the moved-only deps.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/pf-client-core/src/wol.rs

@@ -0,0 +1,24 @@
+//! Client-side Wake-on-LAN: parse stored MAC strings and hand them to the shared core sender
+//! (`punktfunk_core::wol`). A sleeping host has no ARP entry, so the broadcast the core sends is
+//! what actually wakes it; this is called just before connecting to an offline saved host, and
+//! from the explicit "Wake host" menu item / `--wake` CLI mode.
+
+use std::net::Ipv4Addr;
+
+/// Fire a Wake-on-LAN magic packet at `macs` (each `aa:bb:cc:dd:ee:ff`), also unicasting
+/// `last_ip` when given. Best-effort — logs the outcome and never blocks the caller meaningfully
+/// (the core sends a short burst of datagrams and returns).
+pub fn wake(macs: &[String], last_ip: Option<Ipv4Addr>) {
+    let parsed: Vec<[u8; 6]> = macs
+        .iter()
+        .filter_map(|s| punktfunk_core::wol::parse_mac(s))
+        .collect();
+    if parsed.is_empty() {
+        tracing::warn!("wake requested but no valid MAC is known for this host");
+        return;
+    }
+    match punktfunk_core::wol::send_magic_packet(&parsed, last_ip) {
+        Ok(()) => tracing::info!(count = parsed.len(), "sent Wake-on-LAN magic packet"),
+        Err(e) => tracing::warn!(error = %e, "Wake-on-LAN send failed"),
+    }
+}