fix(mail): remove lettre pool (60s stale-connection timeout) + resend button feedback

Cargo.toml

@@ -49,4 +49,4 @@ rand = "0.8"
 clap = { version = "4", features = ["derive", "env"] }
 
 # 注册邮箱验证码发信（rant 2026-08-19T14:36:19：方案 B 完整验证码）
-lettre = { version = "0.11", default-features = false, features = ["builder", "smtp-transport", "rustls-tls", "hostname", "pool"] }
+lettre = { version = "0.11", default-features = false, features = ["builder", "smtp-transport", "rustls-tls", "hostname"] }

src/mail.rs

@@ -10,6 +10,7 @@
 //! `SmtpTransport::builder_dangerous(...).tls(Tls::Opportunistic(...))`。
 
 use anyhow::{Context, Result};
+use std::time::Duration;
 
 use crate::config::Mail;
 use lettre::Transport;
@@ -61,6 +62,8 @@ pub fn send_verification_code(cfg: &Mail, to: &str, code: &str) -> Result<()> {
         .with_context(|| format!("SMTP 服务器不可用: {}", cfg.smtp_host))?
         .port(cfg.smtp_port)
         .credentials(creds)
+        // 显式 15s 超时：避免无 pool 时挂住/长等（rant 2026-08-21T14:08:03）
+        .timeout(Some(Duration::from_secs(15)))
         .build();
     mailer.send(&email).map_err(|e| {
         log::error!("SMTP 发送验证码到 {to} 失败: {e:?}");

ui/js/app.js

@@ -2673,7 +2673,9 @@
       const email = $("#verify-email").value.trim();
       if (!email) return;
       const b = $("#resend-btn");
+      const orig = b.textContent;
       b.disabled = true;
+      b.textContent = T("verify.sending"); // 发送中反馈（rant 2026-08-21T14:08:03 补充验收）
       try {
         const r = await api.post("/api/auth/resend-code", { email });
         if (r.dev_code) { toast(T("verify.devCode") + ": " + r.dev_code, "info"); }
@@ -2682,7 +2684,7 @@
         const m = (err && err.message) ? I18n.mapErr(err.message) : T("verify.err.fail");
         toast(m, "error");
       } finally {
-        setTimeout(() => { b.disabled = false; }, 1000);
+        setTimeout(() => { b.disabled = false; b.textContent = orig; }, 300);
       }
     });
 

ui/js/i18n.js

@@ -65,6 +65,7 @@
     "verify.code": "验证码",
     "verify.submit": "验证并激活",
     "verify.resend": "重新发送",
+    "verify.sending": "发送中…",
     "verify.sent": "验证码已发送到邮箱",
     "verify.ok": "注册成功，请登录",
     "verify.devCode": "[dev] 验证码",
@@ -759,6 +760,7 @@
     "verify.code": "Verification code",
     "verify.submit": "Verify & Activate",
     "verify.resend": "Resend",
+    "verify.sending": "Sending…",
     "verify.sent": "Verification code sent to your email",
     "verify.ok": "Registered successfully, please sign in",
     "verify.devCode": "[dev] Code",