feat: prompt/confirm 替换为自定义弹窗

- shared/utils.js 新增 showConfirm()/showPrompt() 通用函数（inline CSS，无需额外样式）
- admin/common.js 移除重复 showConfirm()，统一使用 utils.js
- admin/posts.js: 3 处 confirm/prompt 替换（审核/退回/锁定）
- admin/comments.js: 1 处 confirm 替换
- settings/index.html: 4 处 confirm + 1 处 prompt 替换
- studio/posts.html + drafts.html: 3 处 confirm 替换
- post-view.js + login.js + post-favorite.js: 3 处 confirm 替换

templates/shared/static/js/utils.js

@@ -91,6 +91,91 @@ function api(method, url, data) {
     return fetch(url, opts).then(function (r) { return r.json(); });
 }
 
+/**
+ * 确认弹窗 — 替代原生 confirm()，统一全站风格
+ * @param {string} title — 弹窗标题
+ * @param {string} message — 提示消息（支持 \n 换行）
+ * @returns {Promise<boolean>} 用户确认返回 true，取消返回 false
+ */
+function showConfirm(title, message) {
+    return new Promise(function(resolve) {
+        var safeTitle = escapeHtml(title);
+        var safeMsg = escapeHtml(message).replace(/\n/g, '<br>');
+
+        var overlay = document.createElement('div');
+        overlay.style.cssText = 'position:fixed;inset:0;background:rgba(0,0,0,0.4);z-index:9998;display:flex;align-items:center;justify-content:center;';
+        overlay.innerHTML = '<div style="background:#fff;border-radius:8px;padding:28px 32px;min-width:320px;max-width:440px;box-shadow:0 8px 30px rgba(0,0,0,0.15);">'
+            + '<h3 style="margin:0 0 12px 0;font-size:17px;color:#2d3436;">' + safeTitle + '</h3>'
+            + '<p style="margin:0 0 20px 0;font-size:14px;line-height:1.6;color:#636e72;">' + safeMsg + '</p>'
+            + '<div style="display:flex;gap:10px;justify-content:flex-end;">'
+            + '<button id="mlbModalCancel" style="padding:8px 20px;border:1px solid #d1d5db;border-radius:6px;background:#fff;color:#374151;font-size:14px;cursor:pointer;">取消</button>'
+            + '<button id="mlbModalConfirm" style="padding:8px 20px;border:none;border-radius:6px;background:#dc2626;color:#fff;font-size:14px;cursor:pointer;">确认</button>'
+            + '</div></div>';
+        document.body.appendChild(overlay);
+
+        function close(val) {
+            overlay.remove();
+            resolve(val);
+        }
+
+        overlay.querySelector('#mlbModalCancel').onclick = function() { close(false); };
+        overlay.querySelector('#mlbModalConfirm').onclick = function() { close(true); };
+        overlay.addEventListener('click', function(e) {
+            if (e.target === overlay) close(false);
+        });
+        // Enter 键确认
+        var onKey = function(e) {
+            if (e.key === 'Enter') { document.removeEventListener('keydown', onKey); close(true); }
+            if (e.key === 'Escape') { document.removeEventListener('keydown', onKey); close(false); }
+        };
+        document.addEventListener('keydown', onKey);
+    });
+}
+
+/**
+ * 输入弹窗 — 替代原生 prompt()，统一全站风格
+ * @param {string} message — 提示文本
+ * @param {string} [defaultValue=''] — 输入框默认值
+ * @returns {Promise<string|null>} 用户输入的值，取消返回 null
+ */
+function showPrompt(message, defaultValue) {
+    return new Promise(function(resolve) {
+        var safeMsg = escapeHtml(message);
+
+        var overlay = document.createElement('div');
+        overlay.style.cssText = 'position:fixed;inset:0;background:rgba(0,0,0,0.4);z-index:9998;display:flex;align-items:center;justify-content:center;';
+        overlay.innerHTML = '<div style="background:#fff;border-radius:8px;padding:28px 32px;min-width:320px;max-width:440px;box-shadow:0 8px 30px rgba(0,0,0,0.15);">'
+            + '<p style="margin:0 0 16px 0;font-size:14px;line-height:1.6;color:#2d3436;">' + safeMsg + '</p>'
+            + '<input id="mlbPromptInput" type="text" style="width:100%;padding:10px 12px;border:1px solid #d1d5db;border-radius:6px;font-size:14px;color:#2d3436;outline:none;box-sizing:border-box;" value="' + escapeHtml(defaultValue || '') + '" placeholder="">'
+            + '<div style="display:flex;gap:10px;justify-content:flex-end;margin-top:16px;">'
+            + '<button id="mlbPromptCancel" style="padding:8px 20px;border:1px solid #d1d5db;border-radius:6px;background:#fff;color:#374151;font-size:14px;cursor:pointer;">取消</button>'
+            + '<button id="mlbPromptConfirm" style="padding:8px 20px;border:none;border-radius:6px;background:#0984e3;color:#fff;font-size:14px;cursor:pointer;">确认</button>'
+            + '</div></div>';
+        document.body.appendChild(overlay);
+
+        var input = overlay.querySelector('#mlbPromptInput');
+
+        function close(val) {
+            overlay.remove();
+            resolve(val);
+        }
+
+        overlay.querySelector('#mlbPromptCancel').onclick = function() { close(null); };
+        overlay.querySelector('#mlbPromptConfirm').onclick = function() { close(input.value); };
+        overlay.addEventListener('click', function(e) {
+            if (e.target === overlay) close(null);
+        });
+        // Enter 确认，Escape 取消
+        var onKey = function(e) {
+            if (e.key === 'Enter') { document.removeEventListener('keydown', onKey); close(input.value); }
+            if (e.key === 'Escape') { document.removeEventListener('keydown', onKey); close(null); }
+        };
+        document.addEventListener('keydown', onKey);
+        // 自动聚焦输入框
+        setTimeout(function() { input.focus(); input.select(); }, 50);
+    });
+}
+
 // 全局头像图片加载失败回退（替代 onerror 内联事件，满足 CSP 无 unsafe-inline）
 document.addEventListener('error', function(e) {
     var img = e.target;