🔧 Remove coverage in clean target

clean only wiped dist, leaving the gitignored coverage/ tree to
accumulate across runs. Remove both so a clean checkout state is
actually reachable.

backlog.tasks

@@ -38,8 +38,8 @@ Setup:
 ☐ Confirm pre-push gate strength
     - pre-push runs `npm test` (`check:tsc` + tests), not full `check`; oxlint/oxfmt/cspell drift on unstaged content is only caught per-staged-file at commit or whole-project in CI
     ☐ Confirm this is intended per the feedback-tier table, or point pre-push at `verify`
-☐ Clean stale `coverage/` in `npm run clean`
-    ☐ `npm run clean` only removes `dist`; add `coverage` (both are gitignored but bloat the working tree)
+✔ Clean stale `coverage/` in `npm run clean` @done
+    ✔ `npm run clean` only removes `dist`; add `coverage` (both are gitignored but bloat the working tree) @done
 ☐ Drop redundant `main`/`types` top-level fields
     ☐ `exports` is the source of truth; `main`/`types` are redundant (harmless, but publint/ATTW prefer `exports`)
 ☐ Silence the knip `@runwisp/pubv` false positive