fix: preserve unit sprites until their death animation plays in pre-resolved turns

Units doomed to die later in a pre-resolved enemy turn were being removed
from the board prematurely during sync, before their death animation could
play. Now:

- syncUnits only prunes dead views on actual army elimination, not on
  mid-turn CO powers that would kill units later in the same turn
- Added 'loaded'/'joined' event handlers to remove views when units merge
  into transports at the correct animated moment
- setUnitVisibility skips views whose units are already gone from state,
  preserving mid-replay sprites until their event fires

src/games/advancewars/AdvanceWarsGame.js

@@ -553,6 +553,15 @@ export default class AdvanceWarsGame extends Phaser.Scene {
           const v = run.view.unitViews.get(e.unitId);
           if (v) { v.c.destroy(); run.view.unitViews.delete(e.unitId); }
         }
+        if (e.type === 'loaded' || e.type === 'joined') {
+          // unit merged into a transport / another unit — remove its now
+          // defunct board sprite once its move-in has been animated (no
+          // explosion). Reaped here rather than by a state-diff sync so it
+          // vanishes at this exact moment, not early (state is already the
+          // whole turn's final result — see syncUnits' prune note).
+          const v = run.view.unitViews.get(e.unitId);
+          if (v) { v.c.destroy(); run.view.unitViews.delete(e.unitId); }
+        }
         if (e.type === 'powerFired') {
           await new Promise((resolve) => Screens.powerCutIn(this, this.rules, this.oppById, run.state.armies[e.army].co, e.army, resolve));
           run.hud.refresh(run.state, 0);
@@ -570,9 +579,16 @@ export default class AdvanceWarsGame extends Phaser.Scene {
       // full-screen reveal, so those still do a full sync.
       const wideReveal = events.some((e) =>
         ['powerFired', 'healedAll', 'refreshed', 'tsunami', 'meteor', 'armyEliminated'].includes(e.type));
+      // A wide effect snaps every unit to its (final) state, but only an
+      // actual army elimination may *prune* dead views here — otherwise a
+      // mid-turn CO power would reap units merely doomed to die later in this
+      // same pre-resolved turn, yanking them off the board before their own
+      // death animation plays. Non-elimination deaths are reaped by the
+      // 'destroyed'/'crashed' handlers above, at the moment they animate.
+      const eliminated = events.some((e) => e.type === 'armyEliminated');
       const touchedIds = wideReveal ? null : new Set(events.flatMap((e) =>
         [e.unitId, e.attackerId, e.defenderId, e.transportId, e.intoId, e.byId].filter((id) => id != null)));
-      run.view.syncUnits(touchedIds);
+      run.view.syncUnits(touchedIds, { prune: eliminated });
       run.view.refreshFog(0);
       run.hud.refresh(run.state, 0);
       if (enemy && (moved || battles.length || capturing)) await this.wait(500);

src/games/advancewars/AdvanceWarsMapView.js

@@ -442,7 +442,7 @@ export class AdvanceWarsMapView {
   // Used by replayEvents to reveal a turn's units one action at a time
   // instead of snapping everyone straight to the turn's final result. Pass
   // nothing (or null) for a full sync — creates/updates/prunes everyone.
-  syncUnits(onlyIds = null) {
+  syncUnits(onlyIds = null, { prune = !onlyIds } = {}) {
     const { state, rules, scene } = this;
     const present = new Set();
     for (const u of state.units) {
@@ -473,11 +473,12 @@ export class AdvanceWarsMapView {
       }
       if (justCreated || !onlyIds || onlyIds.has(u.id)) this.placeUnit(u, v);
     }
-    // Stale-view cleanup only runs on a full sync — a scoped pass can't
-    // tell a genuinely-dead unit from one whose own (not yet replayed)
-    // death is later in this same turn's log; the 'destroyed'/'crashed'
+    // Stale-view cleanup only runs when explicitly pruning (a full sync, by
+    // default) — a mid-replay pass can't tell a genuinely-dead unit from one
+    // whose own (not yet replayed) death/load/join is later in this same
+    // pre-resolved turn's log; the 'destroyed'/'crashed'/'loaded'/'joined'
     // event handlers already remove views at the right moment for that.
-    if (!onlyIds) {
+    if (prune) {
       for (const [id, v] of [...this.unitViews]) {
         if (!present.has(id)) { v.c.destroy(); this.unitViews.delete(id); }
       }
@@ -507,7 +508,15 @@ export class AdvanceWarsMapView {
   }
 
   setUnitVisibility(visibleIds) {
+    // Views whose unit is already gone from state are mid-replay: the enemy
+    // turn is resolved up front, so a unit that dies (or loads/joins) later
+    // this turn vanishes from state while its board sprite is deliberately
+    // held until its own event is replayed (see syncUnits / replayEvents).
+    // Never force-hide those here — leave them exactly as last shown, so a
+    // doomed unit stays put until its death animation actually plays.
+    const alive = new Set(this.state.units.map((u) => u.id));
     for (const [id, v] of this.unitViews) {
+      if (!alive.has(id)) continue;
       v.c.setVisible(visibleIds.has(id));
     }
   }