Add message branching

Updated the behaviour of commands:

- `lmcli edit`
  - by default create a new branch/message branch with the edited contents
  - add --in-place to avoid creating a branch
  - no longer delete messages after the edited message
  - only do the edit, don't fetch a new response
- `lmcli retry`
  - create a new branch rather than replacing old messages
  - add --offset to change where to retry from

pkg/lmcli/lmcli.go

@@ -36,7 +36,9 @@ func NewContext() (*Context, error) {
 	}
 
 	databaseFile := filepath.Join(dataDir(), "conversations.db")
-	db, err := gorm.Open(sqlite.Open(databaseFile), &gorm.Config{})
+	db, err := gorm.Open(sqlite.Open(databaseFile), &gorm.Config{
+		//Logger: logger.Default.LogMode(logger.Info),
+	})
 	if err != nil {
 		return nil, fmt.Errorf("Error establishing connection to store: %v", err)
 	}