Improve multiplayer sync and controls responsiveness

- force host snapshot on round-end transitions to prevent client desync/timeouts\n- add smoother non-host snapshot reconciliation and higher snapshot cadence\n- send periodic input heartbeats for remote control freshness\n- allow bomb placement while moving for local and multiplayer players\n- keep host-only next-round restart flow in-match

src/game.js

@@ -860,12 +860,12 @@ function applySnapshot(snapshot) {
   rebuildFireLookup();
 }
 
-function broadcastSnapshot() {
+function broadcastSnapshot(force = false) {
   if (!network.isHost || state.mode !== "multiplayer" || state.screen !== "game") {
     return;
   }
   const t = now();
-  if (t - network.lastSnapshotSentAt < 1 / SNAPSHOT_RATE) {
+  if (!force && t - network.lastSnapshotSentAt < 1 / SNAPSHOT_RATE) {
     return;
   }
   network.lastSnapshotSentAt = t;
@@ -1371,9 +1371,10 @@ function checkDeaths() {
 
 function evaluateOutcome() {
   if (state.status !== "running") {
-    return;
+    return false;
   }
 
+  let endedThisFrame = false;
   const alivePlayers = state.players.filter((player) => player.alive);
 
   if (state.mode === "single") {
@@ -1406,8 +1407,10 @@ function evaluateOutcome() {
   }
 
   if (state.status === "ended") {
+    endedThisFrame = true;
     openMenu();
   }
+  return endedThisFrame;
 }
 
 function updateNonHostClient(dt) {
@@ -1521,10 +1524,10 @@ function updateGame(dt) {
     collectPowerup(player);
   }
 
-  evaluateOutcome();
+  const endedThisFrame = evaluateOutcome();
 
   if (state.mode === "multiplayer" && network.isHost) {
-    broadcastSnapshot();
+    broadcastSnapshot(endedThisFrame);
   }
 }