Add project scope for repo-local dotfiles

[polymorcodeus]

Summary

Adds project scope: manage repo-local dotfiles (.vscode/, .crush/, AGENTS.md) that live inside a git repository, backed up to the lnk repo but not committed upstream. Completes the project-scope work ahead of the v2.0.0 release.

What's new

• Core workflow - init, add/list/untrack patterns, push/restore/pull.
• Lifecycle parity - project remove (restore files, drop storage) and project forget (unlink, keep storage), plus reconcile-on-untrack and a project sync command that reconciles patterns, live files, and storage.
• Global patterns - project add/untrack --global manage the repo-root .lnkinclude; local ! patterns negate a global include per project.
• Discovery + health - project list --all lists stored projects; lnk doctor reports stored projects, unmarked storage, and empty project dirs.

Usage

Command	Purpose
project init / add <pattern> / untrack [--keep] <pattern>	manage .lnkinclude
project push [--force] / sync [--dry-run] [--prune-deletions] [--force]	move/reconcile files
project restore [--dry-run] [--force] / pull [--force]	recreate symlinks
project remove / forget	stop managing (restore vs keep storage)
project list [--all]	patterns, or stored projects

Behavior changes / guardrails

• All project commands anchor at the git toplevel; running from a subdirectory is safe.
• Project commands refuse to run inside the lnk repo (or any clone of it) to prevent self-storage.
• Files tracked by the project's own git are skipped by push/sync/restore with a warning (add !path or --force), avoiding a committed file becoming a machine-local symlink.
• project untrack reconciles by default (mirrors lnk remove); --keep restores edit-only behavior.
• Deletions are never auto-propagated: sync reports them, and only --prune-deletions removes their stored copies.
• Files are managed individually, not as directory symlinks; local-only repos (no origin) get a local/<name>-<hash> storage ID.

Testing

• Unit tests alongside each collaborator cover the guardrails, reconciliation, lifecycle, global patterns, and doctor integration.
• make check runs fmt, vet, lint, unit, and integration suites; all green.