add-code-comments

# Add Code Comments Systematically review and improve code comments across the entire Go codebase. If `$ARGUMENTS` is provided, limit scope to the listed packages/directories (e.g., `internal/runner internal/store`). Otherwise, process everything. ## Objectives 1. **Add doc comments** to all exported types, functions, methods, and constants that lack them. Follow Go conventions (`// FuncName does ...`). 2. **Add inline comments** explaining non-trivial logic: complex conditionals, concurrency patterns, algorithmic steps, subtle edge-case handling, non-obvious side effects, and "why" behind design choices. 3. **Improve existing comments** that are vague, outdated, or misleading. Do not remove accurate comments. 4. **Note bugs** — if you discover what appears to be a bug (logic error, race condition, missing error check, off-by-one, etc.), do NOT fix it. Instead, append an entry to `BUGS.md` at the repo root with: file path, line range, description of the suspected bug, and why you think it is a bug. 5. **Do not change any logic** — only comments and `BUGS.md`. No refactoring, no formatting changes, no import reordering. ## Step 0: Inventory 1. Run `find . -name '*.go' -not -path './vendor/*' | wc -l` to gauge scope. 2. Read `CLAUDE.md` to refresh awareness of project conventions. 3. Read `BUGS.md` if it exists, so you don't duplicate entries. 4. Group Go packages into the batches defined in Step 1. ## Step 1: Parallel sub-agent batches Launch sub...