chore: add and update gitignore rules for project files

add a comprehensive gitignore file to exclude unnecessary files like dependencies, runtime data, uploads, local configs and debug temporary files

public/tools/private_clipboard/index.html

@@ -9,7 +9,23 @@
     <link rel="stylesheet" href="/tools/private_clipboard/clipboard.css" />
   </head>
   <body>
-    <main class="pc-main">
+    <!-- 登录界面 -->
+    <section id="pc-auth" class="pc-auth-card">
+      <h2>私人剪贴板 - 登录</h2>
+      <div class="pc-auth-form" autocomplete="off">
+        <input id="pc-login-user" placeholder="用户名" autocomplete="off" readonly />
+        <input id="pc-login-pass" placeholder="密码" type="password" autocomplete="off" readonly />
+        <button id="pc-btn-login" class="btn">登录</button>
+      </div>
+      <div id="pc-auth-status" class="pc-auth-status" style="display:none"></div>
+    </section>
+
+    <!-- 主应用界面 -->
+    <main id="pc-app" class="pc-main" style="display:none">
+      <div class="pc-topbar">
+        <span class="pc-topbar-title">私人剪贴板</span>
+        <button id="pc-btn-logout" class="btn pc-btn-logout" type="button">注销</button>
+      </div>
       <section class="pc-input">
         <div id="paste-zone" class="pc-paste-zone pc-desktop-only" tabindex="0">
           <div class="pc-paste-text">在这里粘贴文字 / 图片 / 文件</div>