feature: add task editing

[Sa4eNecHinS]

Summary

Adds support for editing existing tasks from the task list.

Users can now select a task, edit its contents (with E), and save the changes without deleting and recreating the task.

Changes

• Added support for editing the currently selected task.
• Added special keyboard shortcuts to enter edit mode. (E or shift + e)
• Reuse an existing flow to edit tasks.
• Added validation for edited task values.
• Preserved the existing task state while updating its content.
• Added support for editing in two modes: basic and regular
• README Update
• Added task edit validation tests.

Testing

The changes were tested with:

go test ./...
go build ./...
go vet ./...
gofmt -l .

Tests successfully completed at terminal