feat(linux-client): WOL wait-until-up + IP re-key (Apple/Android parity)

The Linux client already had WOL send + MAC storage + a Wake action + auto-wake-
on-connect, but the auto-wake just fired a packet and did one dial to the stored
address — so a host that woke on a new DHCP lease failed, and there was no
"waiting" feedback. Add the polished flow (mirrors Apple/Android HostWaker):

- ui_trust::wake_and_connect — send the magic packet, poll mDNS until the host
  reappears (re-sending every 6 s, 90 s budget) behind a cancelable "Waking…"
  dialog, then connect; if it woke on a new IP, re-key the saved host first.
- trust::rekey_addr — no-churn addr/port update keyed by fingerprint.
- the hosts page routes an offline saved-host-with-MAC tap to on_wake_connect
  (the new flow) instead of fire-and-forget wake + immediate dial.

Builds + clippy + fmt clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

clients/linux/src/trust.rs

@@ -168,6 +168,26 @@ pub fn learn_mac(fp_hex: &str, addr: &str, port: u16, mac: &[String]) {
     let _ = known.save();
 }
 
+/// Re-key a saved host's address/port after it rediscovered on a new DHCP lease (matched by
+/// fingerprint). No-op — and no disk write — when unchanged. Called from the wake-and-wait flow when
+/// a woken host reappears on a different IP than the stored one, so this and future connects dial the
+/// live address instead of the stale one.
+pub fn rekey_addr(fp_hex: &str, addr: &str, port: u16) {
+    if fp_hex.is_empty() {
+        return;
+    }
+    let mut known = KnownHosts::load();
+    let Some(h) = known.hosts.iter_mut().find(|h| h.fp_hex == fp_hex) else {
+        return;
+    };
+    if h.addr == addr && h.port == port {
+        return;
+    }
+    h.addr = addr.to_string();
+    h.port = port;
+    let _ = known.save();
+}
+
 /// Stamp "now" as this host's last successful connect (drives the hosts page's
 /// most-recent accent). No-op when the fingerprint isn't stored.
 pub fn touch_last_used(fp_hex: &str) {