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/clipboard.css

@@ -4,6 +4,68 @@ body {
   font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
 }
 
+/* ===== 登录界面 ===== */
+.pc-auth-card {
+  max-width: 360px;
+  margin: 120px auto 0;
+  padding: 32px 28px;
+  background: #1a1d24;
+  border: 1px solid #2a2d35;
+  border-radius: 12px;
+  text-align: center;
+}
+.pc-auth-card h2 {
+  margin: 0 0 24px;
+  font-size: 20px;
+  font-weight: 600;
+}
+.pc-auth-form {
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+}
+.pc-auth-form input {
+  padding: 10px 12px;
+  background: #0f1115;
+  border: 1px solid #2a2d35;
+  border-radius: 6px;
+  color: #e6e8ee;
+  font-size: 14px;
+  outline: none;
+}
+.pc-auth-form input:focus {
+  border-color: #4a9eff;
+}
+.pc-auth-status {
+  margin-top: 12px;
+  font-size: 13px;
+  color: #ff6b6b;
+}
+.pc-auth-status.ok {
+  color: #4ade80;
+}
+
+/* ===== 顶部栏 ===== */
+.pc-topbar {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 16px;
+}
+.pc-topbar-title {
+  font-size: 20px;
+  font-weight: 600;
+}
+.pc-btn-logout {
+  padding: 6px 16px;
+  font-size: 13px;
+  background: #2a2d35;
+  border: 1px solid #3a3d45;
+}
+.pc-btn-logout:hover {
+  background: #3a3d45;
+}
+
 .pc-main {
   max-width: 1100px;
   margin: 0 auto;