Implement Flexible Dependency Management in Setup Script

## Problem
Our current setup script lacks a systematic way to handle external tool dependencies. As we add more tools like git-delta, we're creating increasingly complex installation blocks that are:
- Repetitive
- Hard to maintain
- Not easily extensible

## Proposed Solution
Create a more flexible dependency management system in the setup script that could:
- Define dependencies in a central configuration file
- Support multiple installation methods (package managers, curl, etc.)
- Handle different OS and architecture variations
- Provide clear logging and error handling
- Allow easy addition of new dependencies

## Potential Implementation Ideas
- Use a YAML or JSON configuration file to define dependencies
- Create a generic installation function that can handle different package managers
- Add support for fallback installation methods
- Implement robust logging and error reporting

## Example Pseudo-code
```bash
dependencies:
- name: git-delta
packages:
apt: git-delta
pacman: git-delta
brew: git-delta
fallback:
- curl-install-script
- github-release-download
```

## Acceptance Criteria
- [ ] Create a flexible dependency management system
- [ ] Support major package managers (apt, pacman, brew)
- [ ] Handle OS and architecture variations
- [ ] Provide clear installation feedback
- [ ] Make it easy to add new dependencies

## Additional Considerations
- Performance impact of dependency checks
- Handling of optional vs. required dependencies
- User customization options

Start by locating and reading the setup script, then run it to observe the current dependency-installation behavior. Define the dependency configuration and installation flow from the issue's proposed package-manager, fallback, OS, architecture, logging, and optional-dependency requirements; done means all listed acceptance criteria work and new dependencies can be added easily.

Written by the indexing model from the issue text.