fix:优化工作面板，支持动态字数

app/templates/index.html

@@ -94,6 +94,19 @@
         <label>必须保留观点</label>
         <input id="keepPoints" type="text" placeholder="逗号分隔" />
 
+        <div class="grid2">
+          <div>
+            <label>改写目标字数</label>
+            <input id="targetBodyChars" type="number" min="180" max="2200" step="10" value="500" placeholder="如：500" />
+            <div class="target-chars-quick" aria-label="快捷字数">
+              <button type="button" class="target-char-chip" data-target-chars="300">300</button>
+              <button type="button" class="target-char-chip is-active" data-target-chars="500">500</button>
+              <button type="button" class="target-char-chip" data-target-chars="800">800</button>
+              <button type="button" class="target-char-chip" data-target-chars="1200">1200</button>
+            </div>
+          </div>
+        </div>
+
         <button id="rewriteBtn" class="primary">改写并排版</button>
         <p id="status" class="status"></p>
       </section>
@@ -121,7 +134,7 @@
         <p id="coverHint" class="muted small">未上传时将使用后端默认封面策略。</p>
 
         <div class="field-head">
-          <label>正文（5 自然段，建议 ≤500 字）</label>
+          <label>正文（4~6 自然段，字数由左侧配置）</label>
           <span id="bodyCount" class="meta">0 字</span>
         </div>
         <div class="body-split">