Random events: earthquakes, overflowing rivers, new gold veins (free games and versus, can be switched off)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/src/netplay.rs

@@ -90,6 +90,7 @@ struct Room {
     doc: Option<Value>, // editor campaign of a co-op match (sent to every client at the start)
     resume: Option<(u32, Value)>, // a resumed editor campaign run: its seed and what the masters carry
     surface: bool, // a free match half above ground
+    events: bool,  // random events in a free match
 }
 
 #[derive(Debug)]
@@ -384,7 +385,7 @@ impl Netplay {
         }
         let name = self.clients.get(&conn).map(|c| c.name.clone()).unwrap_or_else(|| "Guest".into());
         let seats = sides.iter().map(|s| (*s, new_seat(*s, false))).collect::<HashMap<_, _>>();
-        let room = Room { code: code.clone(), sides, seats, pending: HashMap::new(), turn: 0, started: false, paused: false, missing: false, seed: None, map_w, map_h, difficulty, mission, doc, resume, surface: msg.get("surface").and_then(|v| v.as_bool()).unwrap_or(false) };
+        let room = Room { code: code.clone(), sides, seats, pending: HashMap::new(), turn: 0, started: false, paused: false, missing: false, seed: None, map_w, map_h, difficulty, mission, doc, resume, surface: msg.get("surface").and_then(|v| v.as_bool()).unwrap_or(false), events: msg.get("events").and_then(|v| v.as_bool()).unwrap_or(false) };
         self.rooms.insert(code.clone(), room);
         if let Some(c) = self.clients.get_mut(&conn) {
             c.room = Some(code.clone());
@@ -652,6 +653,9 @@ impl Netplay {
                 if r.surface {
                     m["surface"] = json!(true);
                 }
+                if r.events {
+                    m["events"] = json!(true);
+                }
                 if let Some((_, carry)) = &r.resume {
                     m["carry"] = carry.clone();
                     m["resume"] = json!(true);