fix: 修复若干问题，添加java lsp

backend/internal/lsp/client.go

@@ -107,7 +107,7 @@ func NewClient(parent context.Context, cfg Config) (*Client, error) {
 		cfg.ClientName = "monica-lsp-gateway"
 	}
 
-	cmd := exec.Command(cfg.Command, cfg.Args...)
+	cmd := exec.Command(filepath.FromSlash(cfg.Command), cfg.Args...)
 	stdin, err := cmd.StdinPipe()
 	if err != nil {
 		return nil, fmt.Errorf("create stdin pipe: %w", err)
@@ -138,7 +138,7 @@ func NewClient(parent context.Context, cfg Config) (*Client, error) {
 	// 独立协程持续读取 stdout 并分发响应。
 	go client.readLoop(stdout)
 
-	initCtx, cancel := context.WithTimeout(parent, 10*time.Second)
+	initCtx, cancel := context.WithTimeout(parent, 30*time.Second)
 	defer cancel()
 
 	if err := client.initialize(initCtx, cfg.RootPath); err != nil {
@@ -277,7 +277,20 @@ func (c *Client) Completion(ctx context.Context, uri string, line, character int
 
 var windowsDrivePattern = regexp.MustCompile(`^[A-Za-z]:`)
 
-// normalizeURI 将相对 file URI 重写为工作区绝对路径 URI。
+// languageExtensions 定义 languageId 对应的规范文件扩展名。
+var languageExtensions = map[string]string{
+	"java":       ".java",
+	"go":         ".go",
+	"javascript": ".js",
+	"typescript": ".ts",
+	"python":     ".py",
+	"c":          ".c",
+	"cpp":        ".cpp",
+	"rust":       ".rs",
+}
+
+// normalizeURI 将相对 file URI 重写为工作区绝对路径 URI，
+// 并将不匹配 languageId 的扩展名（如 .txt）替换为语言对应扩展名。
 func (c *Client) normalizeURI(rawURI string) (string, error) {
 	if rawURI == "" {
 		return "", errors.New("empty uri")
@@ -305,6 +318,14 @@ func (c *Client) normalizeURI(rawURI string) (string, error) {
 		localPath = filepath.Join(c.workspaceDir, filepath.FromSlash(rel))
 	}
 
+	// 若文件扩展名与 languageId 不匹配（如 .txt），替换为语言对应扩展名。
+	if expectedExt, ok := languageExtensions[strings.ToLower(c.languageID)]; ok {
+		currentExt := strings.ToLower(filepath.Ext(localPath))
+		if currentExt != expectedExt {
+			localPath = strings.TrimSuffix(localPath, filepath.Ext(localPath)) + expectedExt
+		}
+	}
+
 	return pathToURI(localPath)
 }