feat: SSR 忘记密码与 Admin SMTP 设置

邮箱验证码重置密码（吊销 session）；后台可配 SMTP 并发送测试信。

Co-authored-by: Cursor <cursoragent@cursor.com>

templates/auth/forgot_password.tmpl

@@ -0,0 +1,33 @@
+{{define "auth/forgot_password"}}
+{{template "base/head" .}}
+<main class="j13-main j13-main--solo j13-auth">
+  <h1>忘记密码</h1>
+  {{template "base/alert" .}}
+  {{if .MailReady}}
+  <form method="post" action="/forgot-password" class="j13-form" id="forgot-form">
+    <input type="hidden" name="_csrf" value="{{.CSRF}}"/>
+    <label>注册邮箱
+      <input type="email" name="email" required autocomplete="email" value="{{.Email}}"/>
+    </label>
+    <label>邮箱验证码
+      <div class="j13-form__row">
+        <input name="email_code" required inputmode="numeric" autocomplete="one-time-code" maxlength="8"/>
+        <button type="submit" formaction="/forgot-password/send-code" formnovalidate class="j13-btn-secondary">发送验证码</button>
+      </div>
+    </label>
+    <label>新密码
+      <input type="password" name="new_password" required autocomplete="new-password" minlength="6"/>
+    </label>
+    <label>确认新密码
+      <input type="password" name="new_password2" required autocomplete="new-password" minlength="6"/>
+    </label>
+    <button type="submit">重置密码</button>
+  </form>
+  <p class="j13-muted">若该邮箱已注册，验证码将发送到邮箱。重置后其它设备会话将失效。</p>
+  {{else}}
+  <p class="j13-muted">邮件服务未配置，无法通过邮箱重置密码。请联系站长在后台配置 SMTP，或使用其它方式找回。</p>
+  {{end}}
+  <p><a href="/login">返回登录</a> · <a href="/">返回首页</a></p>
+</main>
+{{template "base/footer" .}}
+{{end}}