Update outdated URLs and deprecated tool references

[slifty]

Problem

Several tool references, URLs, and dependencies are outdated or deprecated.

Specific Issues

1. Oh My ZSH URL (zsh/install.sh:2)

• Current: https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh
• Should be: https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh
• The project moved from the robbyrussell user to the ohmyzsh organization

2. Unused Homebrew Tap (Brewfile:4)

• isen-ng/dotnet-sdk-versions is tapped but nothing is installed from it
• Either use it or remove it

3. Hub vs GH CLI (git/gitconfig.symlink:4, Brewfile:24)

• .gitconfig references hub which is deprecated
• hub is still in Brewfile but gh (GitHub CLI) is now the official tool
• Consider migrating to gh or documenting why hub is still needed

4. Powerline Fonts Installation (zsh/install.sh:4-9)

• Installs from a GitHub repo that may have newer alternatives
• Consider using Homebrew cask fonts instead: brew install font-powerline-symbols

Impact

• May break in future if URLs change
• Using deprecated tools that won't receive updates
• Potential security vulnerabilities in unmaintained tools

Recommended Actions

1. Update Oh My ZSH installation URL
2. Remove unused tap or document why it's needed
3. Decide on hub vs gh and update accordingly
4. Consider modernizing font installation approach
5. Review all brew packages for deprecation notices

Priority

LOW-MEDIUM - Not immediately broken but should be addressed to prevent future issues