feat: chezmoi dotfile manager support (80-90% token savings)

[jsoyer]

Summary

Adds rtk chezmoi with 9 filtered subcommands covering the full daily chezmoi workflow. Auto-rewrite hook intercepts all commands transparently.

Commands

Command	Output	Savings
chezmoi diff	File-level summary: M .zshrc +3/-1 instead of full git diff	~85%
chezmoi apply	ok ✓ 2 files applied	~90%
chezmoi status	chezmoi status: 1 added, 2 modified + file list	~75%
chezmoi managed	File count grouped by directory	~70%
chezmoi add <files>	ok ✓ 1 file added	~85%
chezmoi re-add <files>	ok ✓ 1 file re-added	~85%
chezmoi update	ok ✓ updated (2 source files changed, 2 dotfiles applied)	~90%
chezmoi unmanaged	File count grouped by directory	~70%
chezmoi doctor	Header summary + warnings/errors only (ok lines suppressed)	~80%

All other subcommands passthrough transparently (e.g. chezmoi edit, chezmoi cd, chezmoi init).

Example output

$ rtk chezmoi diff
chezmoi diff: 2 files
  M .zshrc                                             +3/-1
  A .config/nvim/lua/plugins.lua                       +42

$ rtk chezmoi update
ok ✓ updated (2 source files changed, 2 dotfiles applied)

$ rtk chezmoi update   # nothing to pull
ok ✓ already up to date

$ rtk chezmoi doctor   # all good
chezmoi doctor: ok (12 checks passed)

$ rtk chezmoi doctor   # issues found
chezmoi doctor: 11 ok, 1 warning, 0 errors
warning    key (no GPG key configured)

Test plan

• cargo fmt --all && cargo clippy --all-targets && cargo test — 740 tests, 0 failures
• 31 chezmoi-specific unit tests with token savings assertions (≥60% each)
• Hook rewrite covers all 9 subcommands
• chezmoi doctor preserves non-zero exit code when issues found
• chezmoi update handles both "already up to date" and actual pull cases

🤖 Generated with Claude Code

[aeppling]

Hello,

Thanks for contributing,
Please read CONTRIBUTING.md, your branch should be from develop and the PR should target develop branch

Then we will be able to review & merge if valid :)

[jsoyer]

Closing in favor of #436 which correctly targets the develop branch as per CONTRIBUTING.md.