simplify

Simplify recently changed code while preserving exact behavior: same output for every input, same error behavior, same side effects and ordering. Prioritize readable, explicit code over compact code — fewer lines is not the goal. ## Step 1: Resolve the scope 1. **If the user named a scope** (a file, a directory, "the function I just wrote"), use it as authoritative — do not widen it. 2. **Otherwise**, use the diff between the current branch and its merge-base with the default branch (`git diff <default-branch>...`). With no base ref, fall back to staged + unstaged changes (`git diff HEAD`). 3. **Outside a git repository**, use the files edited earlier in this conversation. If the scope comes up empty, stop and ask the user what to simplify. **Preflight:** the reviewers hunt in _code_. If the scope is documentation-only, or only generated, vendored, lockfile, or mechanical churn (formatting, lint autofix, mass rename), stop with a one-line note that there is nothing to simplify. On a mixed diff, narrow the scope to the code files and continue. Gate on the _kind_ of change only — a user-named scope always runs. ## Step 2: Launch three reviewers in parallel Dispatch one subagent per persona, in parallel where the harness supports it, sequentially otherwise. For each, read its file and pass the **full file content verbatim** as the subagent's prompt, together with the resolved scope (the full diff or file set) — paraphrasing from memory loses the gating rules that keep t...