ux: 批量下载按钮换多层图标，合并视频开始/停止按钮，延长滚动阈值调至0.7

app/static/public/js/video.js

@@ -3211,12 +3211,12 @@
     // ── 按钮代理：点击 sticky bar 按钮 = 点击原始按钮 ──
     if (mobileStart) {
       mobileStart.addEventListener('click', () => {
-        if (startBtn && !startBtn.disabled) startBtn.click();
-      });
-    }
-    if (mobileStop) {
-      mobileStop.addEventListener('click', () => {
-        if (stopBtn && !stopBtn.disabled) stopBtn.click();
+        const running = stopBtn && !stopBtn.classList.contains('hidden');
+        if (running) {
+          if (stopBtn && !stopBtn.disabled) stopBtn.click();
+        } else {
+          if (startBtn && !startBtn.disabled) startBtn.click();
+        }
       });
     }
     if (mobileSplice) {
@@ -3225,14 +3225,22 @@
       });
     }
 
-    // ── 同步生成按钮状态（running / idle）到 sticky bar ──
+    // ── 同步生成按钮状态（running / idle）到一体切换按钮 ──
     function syncGenerateSlotState() {
-      if (!slotGenerate || !mobileStart || !mobileStop) return;
+      if (!mobileStart) return;
       const running = stopBtn && !stopBtn.classList.contains('hidden');
-      mobileStop.classList.toggle('hidden', !running);
-      mobileStart.classList.toggle('hidden', running);
-      slotGenerate.classList.toggle('is-running', running);
-      if (mobileStart) mobileStart.disabled = Boolean(startBtn && startBtn.disabled);
+      // 切换图标
+      const playIcon = mobileStart.querySelector('.mobile-gen-play');
+      const stopIcon = mobileStart.querySelector('.mobile-gen-stop');
+      const label = mobileStart.querySelector('.mobile-gen-label');
+      if (playIcon) playIcon.style.display = running ? 'none' : '';
+      if (stopIcon) stopIcon.style.display = running ? '' : 'none';
+      if (label) label.textContent = running ? '停止' : '开始生成';
+      // 切换样式：running 时改为 outline 风格
+      mobileStart.className = running
+        ? 'geist-button-outline mobile-action-btn gap-2'
+        : 'geist-button mobile-action-btn gap-2';
+      mobileStart.disabled = !running && Boolean(startBtn && startBtn.disabled);
     }
 
     if (startBtn || stopBtn) {
@@ -3253,7 +3261,7 @@
           if (slotGenerate) slotGenerate.classList.toggle('mobile-action-slot--active', !spliceVisible);
           if (slotSplice)   slotSplice.classList.toggle('mobile-action-slot--active', spliceVisible);
         },
-        { threshold: 0.15 }
+        { threshold: 0.7 }
       );
       io.observe(targetPanel);
     }

app/static/public/pages/imagine.html

@@ -19,7 +19,7 @@
   <link href="/static/vendor/geist/geist-mono.css" rel="stylesheet">
   <script src="/static/common/js/theme.js?v=0.1.0"></script>
   <link href="/static/common/css/common.css?v=0.3.8" rel="stylesheet">
-  <link href="/static/public/css/imagine.css?v=0.5.0" rel="stylesheet">
+  <link href="/static/public/css/imagine.css?v=0.5.1" rel="stylesheet">
   <link href="/static/common/css/toast.css" rel="stylesheet">
 </head>
 
@@ -299,12 +299,13 @@
             <path d="M10 11v6M14 11v6"/><path d="M9 6V4h6v2"/>
           </svg>
         </button>
-        <!-- 批量下载 -->
-        <button class="im-icon-btn" id="imBatchBtn" type="button" title="批量下载" aria-label="批量下载">
+        <!-- 批量下载全部（layers 图标，与下载选中区分） -->
+        <button class="im-icon-btn" id="imBatchBtn" type="button" title="批量下载全部" aria-label="批量下载">
           <svg width="17" height="17" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"
             stroke-linecap="round" stroke-linejoin="round">
-            <path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"/>
-            <polyline points="7 10 12 15 17 10"/><line x1="12" y1="15" x2="12" y2="3"/>
+            <polygon points="12 2 2 7 12 12 22 7 12 2"/>
+            <polyline points="2 17 12 22 22 17"/>
+            <polyline points="2 12 12 17 22 12"/>
           </svg>
         </button>
         <!-- 全选 -->

app/static/public/pages/video.html

@@ -313,21 +313,18 @@
       </button>
       <!-- 右：操作区，根据上下文滑动切换 -->
       <div class="mobile-action-ops">
-        <!-- 生成模式（默认） -->
+        <!-- 生成模式（默认）：开始/停止一体切换按钮 -->
         <div id="mobileBarGenerate" class="mobile-action-slot mobile-action-slot--active">
           <button id="mobileStartBtn" class="geist-button mobile-action-btn gap-2" type="button">
-            <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"
+            <svg class="mobile-gen-play" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"
               stroke-linecap="round" stroke-linejoin="round">
               <polygon points="5 3 19 12 5 21 5 3" />
             </svg>
-            开始生成
-          </button>
-          <button id="mobileStopBtn" class="geist-button-outline mobile-action-btn gap-2 hidden" type="button">
-            <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"
-              stroke-linecap="round" stroke-linejoin="round">
+            <svg class="mobile-gen-stop" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"
+              stroke-linecap="round" stroke-linejoin="round" style="display:none">
               <rect x="5" y="5" width="14" height="14" />
             </svg>
-            停止
+            <span class="mobile-gen-label">开始生成</span>
           </button>
         </div>
         <!-- 延长模式（滚到延长区时） -->
@@ -354,7 +351,7 @@
   <script src="/static/common/js/toast.js"></script>
   <script src="/static/common/js/prompt-enhancer.js?v=0.1.15"></script>
   <script src="/static/common/js/pwa.js?v=0.1.1"></script>
-  <script src="/static/public/js/video.js?v=0.6.3"></script>
+  <script src="/static/public/js/video.js?v=0.6.4"></script>
 </body>
 
 </html>