Add Linux support

[simono]

Summary

• Makes dotfiles cross-platform by adding Linux support alongside macOS
• Splits package management into platform-specific and shared configurations
• Adds tmux configuration and comprehensive Linux setup documentation

Key Changes

Package Management

• Split Brewfile into cross-platform core packages and Brewfile.mac for macOS-specific tools
• Platform-aware update scripts that conditionally install macOS packages (mas, GUI apps)

Shell Configuration

• Updated fish Homebrew config to detect both macOS (/opt/homebrew) and Linux (/home/linuxbrew/.linuxbrew) paths
• Fixed television cable override loop to use proper fish syntax

Configuration

• Added tmux configuration with sensible defaults
• Changed vim-sneak submodule to HTTPS for easier cloning without SSH keys
• Fixed Brewfile.local check to handle missing files gracefully

Documentation

• New Linux setup guide covering prerequisites, Homebrew, Rust toolchain, unattended upgrades, and shell configuration

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This pull request adds Linux support to the dotfiles repository, making it cross-platform while maintaining macOS compatibility. The changes split package management into platform-specific and shared configurations, add tmux configuration, and provide comprehensive Linux setup documentation.

Changes:

• Split Homebrew packages into cross-platform Brewfile and macOS-specific Brewfile.mac
• Added platform detection to update scripts to conditionally run macOS-specific commands
• Enhanced fish shell Homebrew configuration to support both macOS and Linux installation paths
• Added tmux configuration file with sensible defaults
• Changed vim-sneak git submodule from SSH to HTTPS URL for easier cloning
• Added comprehensive Linux setup documentation

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tmux/tmux.conf	New tmux configuration with sensible defaults for window/pane numbering and mouse support
fish/functions/so-dotfiles-update.fish	Added platform detection to run macOS-specific updates only on Darwin systems
fish/conf.d/homebrew.fish	Updated to detect and configure Homebrew on both macOS and Linux paths
dotbot-update.yaml	Removed macOS-specific commands and ~/.Brewfile symlink, added defensive error handling
dotbot-update-mac.yaml	New file containing macOS-specific update commands (mas, softwareupdate, Brewfile.mac)
dotbot-config.yaml	Fixed television cable override loop to use proper fish syntax
Brewfile	Removed macOS-specific packages to create cross-platform core package list
Brewfile.mac	New file containing all macOS-specific packages (casks, mas apps)
.gitmodules	Changed vim-sneak URL from SSH to HTTPS for consistency with other submodules
docs/linux.md	New comprehensive Linux setup guide with prerequisites and configuration steps

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