cupertino-handbook-draftlisted

Draft `.cupertino/<domain>-handbook.md` by analyzing this project one dimension at a time, never inventing evidence, and marking honestly what's scaffolded versus observed. ## Steps 1. **Parse the domain** from the first argument — must be exactly one of `code`, `design`, `testing`, `documentation`. If it's anything else, say so and stop; don't guess a mapping. 2. **Check for an existing handbook** at `.cupertino/<domain>-handbook.md`. If it exists, **ask the user explicitly** whether to overwrite before doing anything else — do not proceed silently. (A PreToolUse hook also enforces this: it refuses to overwrite an existing handbook file unless its first line is the literal marker `<!-- cupertino-overwrite-confirmed -->`. Only include that marker after the user has actually said yes.) 3. **Run the dimension fan-out** via the Workflow tool. First resolve or build the shared symbol-index snapshot: read `analysis/cupertino/current.json`; if missing or its `source_fingerprint` no longer matches, run ``` python3 "${CLAUDE_PLUGIN_ROOT}/scripts/build_symbol_index.py" --repo-path . --plugin-name cupertino ``` (single-flight lock makes concurrent callers safe -- see `references/parallel-safe-research-protocol.md`). For a repo well under ~50 tracked files the build overhead may not be worth it -- skip this and pass `symbolIndexPath: null`. The snapshot isn't code-only: for `design` and `documentation` dimensions it also surfaces CSS selectors/at-rules/custom properties, H