feat: add mise tool manager support for Claude binary discovery

[phatblat]

Summary

• Add support for discovering Claude installations managed by mise (formerly rtx)
• Update source priority to prefer mise installations (rank 3, between homebrew and system)
• Support multiple mise installation paths including legacy rtx and asdf compatibility
• Handle both npm-anthropic-ai-claude-code and generic claude package installations

Changes

• Added find_mise_installations() function to scan mise/rtx/asdf install directories
• Updated source_preference() to include mise installations with appropriate priority
• Added comprehensive path checking for multiple mise directory structures
• Maintains backward compatibility with existing installation discovery methods

Test Plan

• Code follows Rust and Tauri best practices
• No trailing whitespace in changed lines
• Maintains existing functionality for other package managers
• Test mise-installed Claude binary detection on systems with mise
• Verify priority ordering works correctly when multiple installations exist

🤖 Generated with Claude Code