docs: restore the two backlog paths RD-19's target of 0 removed

RD-18 established that a ticket reference inside a path to a document that
still exists is a pointer, not provenance, and exempted one. RD-19 did not
re-run that check against `backend/`, and asserted a target of 0. Two such
paths existed, so the agent described the two documents in prose instead. The
path no longer resolves and the reader must search.

Restore both paths, correct the ticket's decision 1 and acceptance target to
2, and record the miss as the eighth in the README's list.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/project/readable-codebase/README.md

@@ -198,6 +198,15 @@ Three rules when you write a ticket file, because the agent reads its ticket and
      on word boundaries**: `git grep -w machineRemoteData` and
      `git grep -nE "(^|[^a-zA-Z])LoadLifecycle\b"`.
 
+   - RD-19 asserted the backend sweep must reach **0** references, after RD-18 had established
+     that a reference inside a path to a document that still exists is a pointer, not
+     provenance, and exempted one. The supervisor did not run that check against `backend/`.
+     Two such paths existed. The target of 0 gave the agent no way to keep them, so it
+     described the two documents in prose instead — losing a path that resolved. Fixed
+     afterwards; the target is 2. **When a ticket repeats an earlier sweep, re-run the earlier
+     sweep's exemption check against the new scope.** An exemption is a property of the
+     content, not of the directory that happened to hold it first.
+
    Four habits that prevent all five:
 
    - **Use `git grep`, not `grep -r`.** It searches tracked files only, so untracked and