feat: scaffold codespace backend

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

internal/model/file.go

@@ -0,0 +1,24 @@
+package model
+
+// WriteFileRequest is the request body for writing a file.
+type WriteFileRequest struct {
+	Path    string `json:"path"`
+	Content string `json:"content"`
+}
+
+// MkdirRequest is the request body for creating a directory.
+type MkdirRequest struct {
+	Path string `json:"path"`
+}
+
+// RenameRequest is the request body for renaming a file or directory.
+type RenameRequest struct {
+	OldPath string `json:"oldPath"`
+	NewPath string `json:"newPath"`
+}
+
+// ReadFileResponse is the API response for reading a file.
+type ReadFileResponse struct {
+	Path    string `json:"path"`
+	Content string `json:"content"`
+}