Replace custom zsh configuration with oh-my-zsh

[Copilot]

Migrates zsh from a 326-line custom configuration to oh-my-zsh framework while preserving bash setup and workflow-specific git aliases.

Changes

Git alias separation by shell

• Moved git aliases from shell/.config/shell/aliases to shell-specific configs
• bash/.bashrc: All custom git aliases (uses g shortcut + git config aliases: ci, co, st, lg, etc.)
• zsh/.zshrc: Custom git aliases that override oh-my-zsh defaults (gfp, gl, gd, gdm, glm, glc, gw, gwip)

Git workflows now differ intentionally:

• Bash: Uses custom git command shortcuts
• Zsh: oh-my-zsh git plugin + selective custom overrides

Oh-my-zsh integration

• zsh/.zshrc: Minimal config (94 lines) using oh-my-zsh with plugins: git, docker, kubectl, colored-man-pages
• setup.sh: Idempotent installation - installs on first run, updates on subsequent runs
• Preserved shared functions (cdbm, up) and cd alias behavior

Shared shell cleanup

• Removed git aliases from shared config (bash/zsh diverge here)
• Retained non-git aliases (ls variants, utilities, color configs)
• Added note directing users to shell-specific configs for git aliases

Configuration example

# zsh/.zshrc - custom aliases override oh-my-zsh
alias gd='clear && git diff'        # Custom: clears screen first
alias gl='git lg'                   # Custom: uses git lg, not git pull
alias gfp='git fetch && git pull --recurse-submodules && git delete-merged-branches && git-delete-squashed-branches'

Git config dependencies

Some aliases require git config shortcuts:

[alias]
    ci = commit
    co = checkout  
    st = status
    lg = log --graph --pretty=...
    bl = blame
    brem = branch --remote
    gbm = branch --merged
    gr = grep

Validation

• Bash: 11/11 tests passing (unchanged behavior)
• Zsh: 3/3 configuration tests passing
• Setup.sh: Verified idempotent updates

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• esm.ubuntu.com
  • Triggering command: /usr/lib/apt/methods/https /usr/lib/apt/methods/https (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[Copilot]

@mvdbos Unfortunately, I hit an error while trying to use the custom Copilot setup steps configured for this repository and had to close this PR. The error I am seeing is:

no `copilot-setup-steps` job found in your `copilot-setup-steps.yml` workflow file. Please ensure you have a single job named `copilot-setup-steps`. For more details, see https://gh.io/copilot/actions-setup-steps

Once you or someone with the necessary access fixes the problem, please unassign and then reassign issue #0 to me and I'll retry. Thanks!