🔥 Drop redundant main/types fields

exports already declares types + import for the root entry, so the
top-level main/types pair was duplicate metadata. publint and attw stay
green with exports alone, verified against a packed consumer install.

backlog.tasks

@@ -40,8 +40,8 @@ Setup:
     ☐ Confirm this is intended per the feedback-tier table, or point pre-push at `verify`
 ✔ 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`)
+✔ Drop redundant `main`/`types` top-level fields @done
+    ✔ `exports` is the source of truth; `main`/`types` are redundant (harmless, but publint/ATTW prefer `exports`) @done
 ☐ Silence the knip `@runwisp/pubv` false positive
     - `pubv` is a CLI invoked by `release.sh`, not imported, so knip flags it as an unused devDependency and advisory output stays permanently red
     ☐ Add a knip `ignoreDependencies` entry