refactor(grpc): restructure task handling and migrate to slog

Refactor the gRPC client and task handling logic to improve modularity,
error handling, and observability.

- Split `grpc/handler.go` into specialized handler files (login,
  classroom, exams, grades, schedule) to reduce complexity.
- Replace standard `log` with `log/slog` throughout the project for
  structured logging.
- Refactor `grpc/client.go` to use a thread-safe connection management
  pattern with `sync.RWMutex`.
- Remove the legacy `service` package and HTTP server implementation,
  transitioning the application to a pure gRPC runner mode.
- Clean up `config` and `pkg/errors` to remove unused utilities and
  simplify the API.
- Improve error reporting in parsers and HTTP clients by checking
  response status codes.

auth/login.go

@@ -3,8 +3,8 @@ package auth
 import (
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
-	"os"
 	"regexp"
 	"strings"
 
@@ -12,17 +12,15 @@ import (
 	"schedule_converter/config"
 )
 
-// 登录
-func Login(captchaCode string) (bool, error) {
-	return LoginWithClient(client.Client, captchaCode, config.Username, config.Password)
-}
+var nameRegexp = regexp.MustCompile(`(\w+)同学`)
 
 // LoginWithClient 使用指定的 HTTP 客户端和凭据登录
 func LoginWithClient(httpClient *http.Client, captchaCode, username, password string) (bool, error) {
-	fmt.Println("[4] 执行登录...")
+	log := slog.With("username", username)
+	log.Debug("执行登录")
 
 	data := fmt.Sprintf("usercode=%s&password=%s&code=%s", username, password, captchaCode)
-	req, err := http.NewRequest("POST", config.BaseURL+"/login", strings.NewReader(data))
+	req, err := http.NewRequest("POST", config.Get().BaseURL+"/login", strings.NewReader(data))
 	if err != nil {
 		return false, err
 	}
@@ -40,29 +38,20 @@ func LoginWithClient(httpClient *http.Client, captchaCode, username, password st
 		return false, err
 	}
 
-	if client.CheckLoginSuccess(string(body)) {
-		fmt.Println("    ✓ 登录成功！")
-
-		// 提取用户名
-		nameMatch := regexp.MustCompile(`(\w+)同学`).FindStringSubmatch(string(body))
-		if len(nameMatch) > 1 {
-			fmt.Printf("    欢迎, %s!\n", nameMatch[1])
-		}
-
-		// 保存登录后的页面
-		if err := os.WriteFile("login_result.html", body, 0644); err != nil {
-			fmt.Printf("    警告: 无法保存登录页面: %v\n", err)
+	bodyStr := string(body)
+	if client.CheckLoginSuccess(bodyStr) {
+		if match := nameRegexp.FindStringSubmatch(bodyStr); len(match) > 1 {
+			log.Info("登录成功", "name", match[1])
 		} else {
-			fmt.Println("    登录后页面已保存到: login_result.html")
+			log.Info("登录成功")
 		}
-
 		return true, nil
 	}
 
-	fmt.Println("    ✗ 登录失败")
-	if client.IsCaptchaError(string(body)) {
-		fmt.Println("    错误: 验证码错误")
+	if client.IsCaptchaError(bodyStr) {
+		log.Warn("登录失败：验证码错误")
+	} else {
+		log.Warn("登录失败")
 	}
-
 	return false, nil
-}
+}