fix: 修复验证码图片被输入框挤换行，改为右侧同一行

theme.css 全局设定文本输入框 display:block;width:100%，导致验证码图片无法与之同行；改用 flex 容器包裹（输入框 flex:1、图片 flex:none 居右），布局与主题风格一致。

static/public/login.html

@@ -18,8 +18,10 @@
 					<input type="password" id="loginPassword" placeholder="请输入密码">
 					<span id="pwdTip"></span>
 					<label>验证码：</label>
-					<img id="captchaImg" alt="加载中…" title="点击刷新验证码" style="width:120px;height:38px;vertical-align:middle;cursor:pointer;margin-right:8px;border:1px solid #ddd;border-radius:4px;box-sizing:border-box">
-					<input type="text" id="captchaAnswer" placeholder="请输入验证码" maxlength="4" autocomplete="off" style="width:110px">
+					<div style="display:flex;align-items:center;gap:8px">
+						<input type="text" id="captchaAnswer" placeholder="请输入验证码" maxlength="4" autocomplete="off" style="flex:1;min-width:0;width:auto">
+						<img id="captchaImg" alt="加载中…" title="点击刷新验证码" style="width:120px;height:38px;flex:none;cursor:pointer;border:1.5px solid var(--border);border-radius:10px;box-sizing:border-box">
+					</div>
 					<span id="captchaTip"></span>
 				</div>
 				<div class="form-actions">