fix: replace the six Italian user-facing strings with the English wording already used elsewhere

None of them was an isolated slip — each already had an English twin somewhere
else in the system, so this is alignment rather than translation.

The four in `ws.rs` are the slash-command replies (/sethome, /cost x2,
/compact), and the Telegram plugin — the same command set, reached through a
different surface — has said them in English all along. The two surfaces could
answer the same command in two languages. Adopted Telegram's wording verbatim,
and made the /compact "nothing to summarise" line match its twin's spelling
while there.

The two in `skald-relay-server` are the APNs alert body. That one is worth not
re-deriving: it is the *fallback* shown only when the notification service
extension cannot run, and the iOS app localises the same message under the
English key "Action required" (Localizable.xcstrings, en + it). English was
already the canonical form on the other side of the wire — the hardcoded Italian
only ever surfaced in the one case where no locale is negotiated with anyone.

crates/skald-relay-server/src/push.rs

@@ -78,7 +78,7 @@ impl PushItem {
         match self.kind() {
             PushKind::Content => json!({
                 "aps": {
-                    "alert": { "title": "Skald", "body": "Azione richiesta" },
+                    "alert": { "title": "Skald", "body": "Action required" },
                     "badge": 1,
                     "sound": "default",
                     "mutable-content": 1,
@@ -93,7 +93,7 @@ impl PushItem {
             }),
             PushKind::Wake => json!({
                 "aps": {
-                    "alert": { "title": "Skald", "body": "Azione richiesta" },
+                    "alert": { "title": "Skald", "body": "Action required" },
                     "badge": 1,
                     "sound": "default",
                     "content-available": 1

src/frontend/api/ws.rs

@@ -185,8 +185,8 @@ async fn handle_socket(mut socket: WebSocket, skald: Arc<Skald>, source: String,
 
                 if cmd == "/sethome" {
                     let msg = match chat_hub.set_home(&source).await {
-                        Ok(_)  => "🏠 Web impostato come **home**. Le notifiche degli agenti arriveranno qui.".to_string(),
+                        Ok(_)  => "🏠 Web set as **home**. Agent notifications will be delivered here.".to_string(),
-                        Err(e) => format!("⚠️ Errore: {e}"),
+                        Err(e) => format!("⚠️ Error: {e}"),
                     };
                     let _ = socket.send(to_msg(&ServerEvent::Done {
                         message_id:    0,
@@ -238,7 +238,7 @@ async fn handle_socket(mut socket: WebSocket, skald: Arc<Skald>, source: String,
                             let _ = socket.send(to_msg(&ServerEvent::Done {
                                 message_id:    0,
                                 stack_id:      0,
-                                content:       format!("💰 Costo sessione: ${c:.4}"),
+                                content:       format!("💰 Session cost: ${c:.4}"),
                                 input_tokens:  None,
                                 output_tokens: None,
                                 reasoning_content: None,
@@ -248,7 +248,7 @@ async fn handle_socket(mut socket: WebSocket, skald: Arc<Skald>, source: String,
                             let _ = socket.send(to_msg(&ServerEvent::Done {
                                 message_id:    0,
                                 stack_id:      0,
-                                content:       "💰 Nessun costo registrato per questa sessione.".to_string(),
+                                content:       "💰 No cost recorded for this session.".to_string(),
                                 input_tokens:  None,
                                 output_tokens: None,
                                 reasoning_content: None,
@@ -267,7 +267,7 @@ async fn handle_socket(mut socket: WebSocket, skald: Arc<Skald>, source: String,
                             let _ = socket.send(to_msg(&ServerEvent::Done {
                                 message_id:    0,
                                 stack_id:      0,
-                                content:       "✅ Contesto compattato.".to_string(),
+                                content:       "✅ Context compacted.".to_string(),
                                 input_tokens:  None,
                                 output_tokens: None,
                                 reasoning_content: None,
@@ -277,7 +277,7 @@ async fn handle_socket(mut socket: WebSocket, skald: Arc<Skald>, source: String,
                             let _ = socket.send(to_msg(&ServerEvent::Done {
                                 message_id:    0,
                                 stack_id:      0,
-                                content:       "⏩ Compaction skipped (nothing to summarize).".to_string(),
+                                content:       "⏩ Compaction skipped (nothing to summarise).".to_string(),
                                 input_tokens:  None,
                                 output_tokens: None,
                                 reasoning_content: None,