refactor: Extract helper functions from Editor component into separate files

[coderabbitai]

Description

The Editor component in src/components/Editor/index.tsx has grown too large and is exceeding ESLint's line limit. This issue tracks the effort to:

1. Move individual utility functions (like getSelectedLogEventNum, handleCopyLogEventAction, handleWordWrapAction, etc.) into separate files
2. Extract helper components and hooks from the <Editor/> component
3. Reorganize the code to improve maintainability and readability

Implementation Notes

• This refactoring should be done after PR build: Migrate from Webpack to Vite (closes #146, resolves #238). #175 is merged to avoid conflicts
• Consider organizing the extracted functions by their purpose (editor actions, cursor handling, etc.)
• Ensure all existing functionality remains intact after refactoring

Related PRs

• Identified in PR feat: Add toggle for log message prettification (resolves #220). #223 (Add prettifying toggle button)