fix: resolve IDE errors, minor UI tweaks, and implement file conflict resolution UI/API

backend/handlers/tus.go

@@ -107,6 +107,7 @@ func (h *TusHandler) Create(c *fiber.Ctx) error {
 	metadata := parseTusMetadata(c.Get("Upload-Metadata"))
 	fileName := metadata["filename"]
 	destPath := metadata["path"]
+	overwrite := metadata["overwrite"] == "true"
 
 	if fileName == "" {
 		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "filename metadata is required"})
@@ -115,13 +116,15 @@ func (h *TusHandler) Create(c *fiber.Ctx) error {
 		destPath = "."
 	}
 
-	// Resolve destination directory and ensure unique filename
 	destFull, err := resolveSafe(h.Config.StorageDir, destPath)
 	if err != nil {
 		return c.Status(fiber.StatusForbidden).JSON(fiber.Map{"error": "invalid destination path"})
 	}
-	
-	uniqueFileName := GetUniquePath(destFull, fileName)
+
+	uniqueFileName := fileName
+	if !overwrite {
+		uniqueFileName = GetUniquePath(destFull, fileName)
+	}
 
 	// Generate unique upload ID
 	uploadID, err := generateUploadID()