Feature Request: Auto-detect existing dotfile setups and migrate

[grave0x]

Summary

When running dwell setup capture (or a new dwell setup detect subcommand), automatically scan the system for existing dotfile management setups and report what is found — then offer to import/migrate into dwell.

Motivation

Users switching to dwell from other tools need a way to discover what they already have configured. Currently they must manually check for chezmoi, stow, yadm, bare git repos, and other setups. Auto-detection makes migration seamless.

What to detect

Existing dotfile managers

Manager	Detection	Migration
chezmoi	~/.local/share/chezmoi/ exists, or chezmoi source-path	Copy dot_ prefixed files directly into dwell source dir
GNU Stow	~/.stow dir or stow packages in ~/dotfiles/	Copy package files, preserve hierarchy
yadm	~/.config/yadm/ exists, or yadm list	Iterate tracked files, add via dwell add
bare git repo	~/.dotfiles/ with git config status.showUntrackedFiles = no	Add tracked files
dotbot	install.conf.yaml or install.conf.json in common paths	Parse config, add listed files
dotter	~/.config/dotter/ exists, or .dotter/ in home	Parse dotter.toml, add mapped files

Manual dotfile patterns

Beyond specific tools, also detect:

• ~/dotfiles/ or ~/.dotfiles/ directories (common convention)
• ~/.config/ dirs that look like configs (already partially done by dwell)
• Shell rc files that source external scripts from custom paths
• Existing .gitconfig includes pointing to custom configs

Proposed design

dwell setup detect

dwell setup detect                    # Scan and report all found setups
dwell setup detect --json             # Machine-readable output
dwell setup detect --migrate          # Auto-import everything into dwell

Output format:

→ Detecting existing dotfile setups...
✓ chezmoi    found at ~/.local/share/chezmoi (48 tracked files)
✓ yadm       found at ~/.config/yadm (23 tracked files)
✓ bare git   found at ~/.dotfiles (repository)
✓ dotter     found at ~/.config/dotter (config present)
ℹ  ~/dotfiles/ directory exists (15 files)

dwell setup detect --migrate

Auto-import detected setups into the dwell source directory:

→ chezmoi: importing 48 files...
   ✓ dot_bashrc, dot_gitconfig, dot_config/nvim/init.lua ...
→ yadm: importing 23 files...
   ✓ dot_zshrc, dot_ssh/config ...
→ done: 71 files imported from 2 setups

dwell setup detect integration with capture

When running dwell setup capture, also run detection and include results:

{
  "captured_at": "...",
  "detected_setups": {
    "chezmoi": { "path": "~/.local/share/chezmoi", "file_count": 48 },
    "yadm": { "path": "~/.config/yadm", "file_count": 23 }
  }
}

Implementation notes

• Detection is read-only — never modifies existing setups
• --migrate copies files, does not remove originals
• Uses dwell add logic internally to ensure correct dot_ prefixing
• chezmoi: reuse existing SourceDir::detect_chezmoi() method
• dotter: reuse existing SourceDir::detect_dotter() method
• Stow: parse package dirs from ~/dotfiles/stow/ or ~/.stow/
• yadm: shell out to yadm list -a if available
• bare git: check for ~/.dotfiles/.git with bare config

Acceptance criteria

• dwell setup detect scans and reports all common setups
• dwell setup detect --json outputs structured JSON
• dwell setup detect --migrate imports files into dwell source
• Migration adds files with correct dot_ prefix
• Original files are never modified or deleted
• Integration tests verify detection of at least chezmoi and stow