refactor(api): simplify instance management endpoints

- Change delete endpoint to use request body instead of path parameter
- Modify endpoint now takes field as path parameter and instance name in body
- Update README to reflect API changes
- Remove unused description field from software info
- Fix error message in auth token lookup

auth.go

@@ -103,7 +103,7 @@ func GetTokenInfo(userID int) (*TokenInfo, error) {
 
 	tokenInfo, exists := tokenMap[userID]
 	if !exists {
-		return nil, fmt.Errorf("Token not found for userID %d: %s", userID, tokenMap[userID].Token)
+		return nil, fmt.Errorf("Token not found for userID %d", userID)
 	}
 
 	return tokenInfo, nil