fix: 修复支付宝 RSA2 签名问题

- 支持 base64 编码的 PEM 格式私钥（systemd 环境变量）
- 使用 Digest + Pkcs1v15Sign::new() 进行签名（自动哈希）
- 修复 rsa2_sign 和 rsa2_verify 函数实现

src/handlers/payment.rs

@@ -1,9 +1,10 @@
 // handlers/payment.rs — 支付相关处理器（接入支付宝）
 use actix_web::{get, post, web, HttpRequest, HttpResponse};
 use chrono::Utc;
+use rsa::pkcs1v15::{Pkcs1v15Sign, SigningKey, VerifyingKey};
 use rsa::pkcs8::DecodePrivateKey;
-use rsa::signature::{Signer, Verifier};
-use rsa::{Pkcs1v15Sign, RsaPrivateKey};
+use rsa::signature::{SignatureEncoding, Signer, Verifier};
+use rsa::RsaPrivateKey;
 use serde::Deserialize;
 use sha2::{Digest, Sha256};
 use sqlx::postgres::PgPool;
@@ -101,29 +102,30 @@ fn rsa2_sign(content: &str, private_key_pem: &str) -> Result<String, String> {
                 .map_err(|e| format!("私钥解析失败: {}", e))?
         }
     };
-    let hashed_content = Sha256::digest(content.as_bytes());
-    let signature = private_key
-        .sign(Pkcs1v15Sign::new::<Sha256>(), &hashed_content)
-        .map_err(|e| format!("签名失败: {}", e))?;
+    let signing_key = SigningKey::<Sha256>::new(private_key);
+    let signature = signing_key.sign(content.as_bytes());
     Ok(base64::Engine::encode(
         &base64::engine::general_purpose::STANDARD,
-        &signature,
+        signature.to_bytes().as_ref(),
     ))
 }
 
 /// 验证 RSA2 签名
+#[allow(dead_code)]
 fn rsa2_verify(content: &str, sign: &str, public_key_pem: &str) -> Result<bool, String> {
     use rsa::pkcs8::DecodePublicKey;
-    use rsa::signature::Verifier;
+    use rsa::RsaPublicKey;
+    use sha2::Digest;
     let public_key =
-        rsa::RsaPublicKey::from_public_key_pem(public_key_pem)
+        RsaPublicKey::from_public_key_pem(public_key_pem)
             .map_err(|e| format!("支付宝公钥解析失败: {}", e))?;
     let sig_bytes = base64::Engine::decode(&base64::engine::general_purpose::STANDARD, sign)
         .map_err(|e| format!("签名 Base64 解码失败: {}", e))?;
-    let hashed_content = Sha256::digest(content.as_bytes());
-    Ok(public_key
-        .verify(Pkcs1v15Sign::new::<Sha256>(), &hashed_content, &sig_bytes)
-        .is_ok())
+    let hashed = Sha256::digest(content.as_bytes());
+    public_key
+        .verify(rsa::Pkcs1v15Sign::new::<Sha256>(), &hashed, &sig_bytes)
+        .map_err(|e| format!("签名验证失败: {}", e))?;
+    Ok(true)
 }
 
 // ===== Helper: 调用 alipay.trade.page.pay =====