docs: rebalance prose cleanup and add trimming skill

packages/util/timeout/tests/timeout.spec.ts

@@ -172,7 +172,8 @@ describe('timeoutOf', () => {
 describe('deadline — nested deadlines', () => {
   it("does not misclassify an outer deadline's timeout as the inner code", () => {
     // The upstream handed to the inner deadline is ITSELF a deadline that has already timed out
-    // (outer).
+    // (outer). `AbortSignal.any` preserves that reason, but scoping `timeoutOf` to the inner code
+    // must classify it as upstream cancellation rather than the inner capability's timeout.
     const outer = new AbortController()
     outer.abort(new TimeoutReason('OUTER_TIMEOUT', 30))
     using inner = deadline(outer.signal, 60_000, 'BASH_TIMEOUT')