Adopt the standard agent-native flag set, typed exit codes, and
auto-JSON-on-pipe behavior described at https://printingpress.dev/.

- Global flags on every command: --json, --csv, --select, --compact,
  --quiet, --no-color, --no-input, --dry-run.
- Auto-emit JSON when stdout is piped (no flag needed).
- Typed exit codes: 0 success, 2 usage, 3 not found, 4 auth, 5 API,
  7 rate limited. API client maps HTTP status accordingly.
- Errors include a hint pointing at the offending flag/value or the
  remediation step so agents can self-correct in one retry.
- New 'auth doctor' subcommand reports key presence, reachability,
  and authenticated-call validity as a structured check list.
- Shared action wrapper (src/utils/action.js) plumbs global flags
  into every handler and turns CliError into the right exit code.
- Status messages route to stderr; structured data to stdout, so
  pipelines like `bool list | jq` work without losing logs.

In JSON/CSV/piped mode auth status returned early after printing the
payload, leaving exit code 0 even when the health check had failed.
Set EXIT.API before returning, matching how auth doctor already
handles the same case.

Reported by Devin Review on PR #10.

Run `bool git init` to register a `bool` remote, then `git push bool main`
to deploy. Git invokes the new `git-remote-bool` helper when it sees the
`bool::<slug>` URL scheme. The helper:

- Speaks the git remote-helper protocol on stdin/stdout.
- Accepts pushes (we don't track remote refs — empty `list for-push`
  means git treats every local ref as new).
- For each `push <src>:<dst>`, resolves the source ref, materializes it
  into a temporary detached `git worktree`, and runs `bool deploy <slug>`
  there with a `git push <branch> (<sha7>)` commit message.
- Writes `ok <ref>` / `error <ref> <reason>` back so git prints the
  familiar `* [new branch] main -> main` summary.

`bin/git-remote-bool.js` is registered in package.json `bin` so a global
install puts it on PATH alongside `bool`, where git can find it.

The new `bool git init` command adds (or updates) the remote from the
project's `.bool/config` slug.

bool deploy's first-positional-arg heuristic reinterprets the slug as
a directory path when a top-level folder of the same name exists. In a
git-push-to-deploy worktree this meant pushing to e.g. bool::docs would
silently auto-create a new Bool named after the directory instead of
deploying to the intended slug. Pass '.' explicitly to lock the slug in
as a slug.

Reported by Devin Review on PR #11.