Add Configuration Editor UI and Improve Settings Organization

[melonamin]

Add Configuration Editor UI and Improve Settings Organization

Summary

This PR introduces a dedicated Configuration Editor tab in the Settings window and reorganizes the configuration-related UI elements
for better user experience. The editor provides a visual interface for managing SwiftKey's YAML configuration with real-time
validation, undo/redo support, and import/export capabilities.

Changes

🎨 UI Reorganization

• Moved configuration file management from General tab to dedicated Configuration Editor tab

  • Removed configuration file section from GeneralSettingsView (lines 37-117)
  • Relocated all config-related UI elements to ConfigEditorSettingsView

• Improved Configuration Editor layout

  • Moved action buttons from header to bottom toolbar for better accessibility
  • Placed configuration file path display at the bottom with "Change" button nearby
  • Added "Modified" indicator to tree view header (right-aligned) for clear change tracking
  • Reduced excessive bottom padding for more compact UI

🔧 Code Improvements

• Fixed ConfigManager dependency injection

  • Implemented wrapper view pattern in ConfigEditorSettingsView and ConfigEditorView to properly inject ConfigManager into
    @StateObject
  • Fixed preview providers to use ConfigManager.create() without parameters

• Eliminated code duplication

  • Extracted importConfiguration logic to ConfigEditorViewModel to eliminate duplication between views
  • Created shared findItem extension on [MenuItem] array in AppModel.swift
  • Updated MenuTreeView and ValidationIssuesView to use the shared extension