feat: multi-run support — execute N times with one click

- Side Panel: number input next to Auto button (1-50)
- Background: autoRunLoop wraps full flow in a for-loop
  - Each run: reset state (keep VPS/mail settings) → steps 1-9
  - Pause for email on each run, resume continues
  - Stop on error
- Side Panel shows run progress: "Running (2/5)", "Paused (3/5)"
- AUTO_RUN_RESET message resets UI between runs
- Default mail provider changed to 163
- 163 mail: faster polling (500ms intervals), skip child iframe ready signals

sidepanel/sidepanel.html

@@ -18,10 +18,13 @@
       <h1>MultiPage</h1>
     </div>
     <div class="header-btns">
-      <button id="btn-auto-run" class="btn btn-success" title="Run all steps automatically">
-        <svg width="14" height="14" viewBox="0 0 24 24" fill="currentColor"><polygon points="5 3 19 12 5 21 5 3"/></svg>
-        Auto
-      </button>
+      <div class="run-group">
+        <input type="number" id="input-run-count" class="run-count-input" value="1" min="1" max="50" title="Number of runs" />
+        <button id="btn-auto-run" class="btn btn-success" title="Run all steps automatically">
+          <svg width="14" height="14" viewBox="0 0 24 24" fill="currentColor"><polygon points="5 3 19 12 5 21 5 3"/></svg>
+          Auto
+        </button>
+      </div>
       <button id="btn-reset" class="btn btn-ghost" title="Reset all steps">
         <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
           <polyline points="1 4 1 10 7 10"/><path d="M3.51 15a9 9 0 1 0 2.13-9.36L1 10"/>
@@ -47,8 +50,8 @@
       <div class="data-row">
         <span class="data-label">Mail</span>
         <select id="select-mail-provider" class="data-select">
-          <option value="qq">QQ Mail (wx.mail.qq.com)</option>
           <option value="163">163 Mail (mail.163.com)</option>
+          <option value="qq">QQ Mail (wx.mail.qq.com)</option>
         </select>
       </div>
       <div class="data-row">