feat: Enhance Apply Changes UI and fix macOS Icon

[lacerbi]

feat: Enhance Apply Changes UI and fix macOS Icon

Summary

This pull request introduces several user experience enhancements to the "Apply Changes" panel to improve workflow efficiency. It also resolves a persistent bug related to the application icon not displaying correctly on macOS.

Changes Made

Features

• Apply Changes Panel:
  • Adds "Accept All" and "Reject All" buttons to the top navigation bar, allowing users to manage all proposed changes with a single click.
  • Replaces the previous/next navigation text buttons with modern icons for a cleaner and more compact interface.
• Prompt Engineering:
  • Improves the internal prompts to maintain better awareness of the current file being edited, leading to more contextually accurate AI suggestions.

Bug Fixes

• macOS Icon:
  • Implements several fixes to the path construction and loading logic to ensure the Athanor application icon now displays correctly on macOS, both in development and packaged builds.

Testing Done

• Manual verification of UI changes in the "Apply Changes" panel on all platforms.
• Confirmed the application icon now appears as expected on macOS.

Related Issues

• Fixes [FEAT] Prioritize user-provided full file content over prior memory when prompting LLM #42 (although might require further refinements)
• Adds one requested feature (Accept/Reject All) of [FEAT] Apply Changes: per-change controls, navigation, and bulk actions #37