implement-improvements

# Implement Improvements Validate and implement improvements from `.turbo/improvements.md`. ## Step 1: Read the Backlog Read `.turbo/improvements.md`. If the file does not exist, tell the user there are no improvements to implement and stop. Parse all entries, extracting for each: - **Summary** (the `###` heading) - **Category** - **Where** (file paths or areas) - **Why** (rationale) - **Noted** (date) ## Step 2: Validate Against Current Codebase Improvements can go stale: files get renamed, code gets refactored, issues get fixed as side effects of other work. Before planning, validate each improvement. For each entry, verify whether the specific problem or opportunity described in the entry still exists in the code. Do not rely on git log alone. Recent commits touching the same files do not mean the specific issue was addressed. Read the actual code and confirm: 1. **Files exist** — Do the referenced files/paths still exist? If not, the entry is stale. 2. **Problem persists** — Read the relevant code sections. Is the exact issue or opportunity described in the entry still present? This is the primary determination. Check the specific claims: if the entry says a function is uncalled, verify it has no callers; if it says error handling is missing, check whether it was added. Classify each entry as: - **Active** — The described problem or opportunity is confirmed present in the current code - **Stale** — The referenced files no longer exist, or the specific issue has...