fix: QTE false race condition + restore auto-save slot in menu

- QTESystem: add if (!this.active) return guard in setInterval/setTimeout
  callbacks to prevent false result from firing after successful key press
- SaveLoadMenu: restore auto-save slot 0 row with blue styling, thumbnail,
  scene label, and read-only load button

engine/systems/QTESystem.ts

@@ -37,6 +37,7 @@ export class QTESystem {
     document.addEventListener('keydown', this.keyHandler)
 
     this.timerId = setInterval(() => {
+      if (!this.active) return
       const elapsed = Date.now() - startTime
       const remaining = Math.max(0, total - elapsed)
       onUpdate(remaining / 1000, qte.timeLimit)
@@ -47,6 +48,7 @@ export class QTESystem {
     }, this.tickMs)
 
     this.timeoutId = setTimeout(() => {
+      if (!this.active) return
       this.clear()
       onResult(false)
     }, total)

src/components/SaveLoadMenu.vue

@@ -20,6 +20,33 @@ const maxSlots = 5
       <h2 class="save-title">存档 / 读档</h2>
 
       <div class="slot-list">
+        <div class="save-slot auto-save-slot">
+          <div class="slot-thumb">
+            <img
+              v-if="saves.find(s => s.slot === 0)?.thumbnail"
+              :src="saves.find(s => s.slot === 0)!.thumbnail"
+              class="thumb-img"
+            />
+            <span v-else class="thumb-empty">自动</span>
+          </div>
+          <div class="slot-meta">
+            <div class="slot-label auto-save-label">自动存档</div>
+            <div class="slot-info" v-if="saves.find(s => s.slot === 0)">
+              {{ saves.find(s => s.slot === 0)!.sceneLabel }}
+            </div>
+            <div class="slot-info empty" v-else>暂无自动存档</div>
+          </div>
+          <div class="slot-actions">
+            <button
+              class="slot-btn load-btn"
+              :disabled="!saves.find(s => s.slot === 0)"
+              @click="emit('load', 0)"
+            >
+              读取
+            </button>
+          </div>
+        </div>
+
         <div
           v-for="slot in maxSlots"
           :key="slot"
@@ -104,6 +131,15 @@ const maxSlots = 5
   border-radius: 4px;
 }
 
+.auto-save-slot {
+  border-color: rgba(100, 200, 255, 0.3);
+  background: rgba(100, 200, 255, 0.06);
+}
+
+.auto-save-label {
+  color: #6cf;
+}
+
 .slot-thumb {
   width: 64px;
   height: 36px;