harness-init

Scaffold the project-layer harness defined in references/layout-spec.md. Read that spec first if anything below is ambiguous — it is the canon; this file is the procedure.

Hard rules (apply to every phase):

• ADDITIVE ONLY. If a target file already exists, skip it and record the skip. There is no overwrite mode — updating existing files is a manual, diff-reviewed task, not yours.
• Detect before asking. Ask ONE question at a time, each with a recommended default.
• Never touch anything outside the target project directory. The global facts-table row is printed for the user, not applied by you.

Phase 0 — Preconditions

1. Confirm cwd is a git repo root (git rev-parse --show-toplevel equals cwd). Not a repo → stop and ask whether to git init first.
2. Scan which canonical paths already exist (see the tree in references/layout-spec.md). Everything existing goes to the SKIPPED list untouched.