docs: scope acceptance checks to the ticket's files, not a directory

The sixth acceptance-check miss, and the first the executing agent
caught using these rules rather than the supervisor. RD-12 asserted
`git grep "ActionState" -- apps/ssp/src/app/brief` returns nothing, but
org-template.store.ts lives in that directory and is deliberately out of
scope until RD-13. The check could never pass.

Sharpen the existing habit into a mechanical step: name the files, never
a parent directory.

The agent also caught the RD-11 substring trap in its own work, where the
new type BriefActionState contains ActionState, and word-anchored the
check instead of renaming away from the natural name.

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

docs/project/readable-codebase/README.md

@@ -206,8 +206,12 @@ Three rules when you write a ticket file, because the agent reads its ticket and
      which are repo-wide sweeps.
    - **Anchor on a declaration** (`^  onRetry\(\)`), not on a name that may legitimately
      appear elsewhere.
-   - **Keep the Files list consistent with the Acceptance commands.** If a command reaches a
-     file the ticket says not to touch, one of the two is wrong.
+   - **Scope every acceptance command to the ticket's Files list, never to a parent
+     directory.** This is the habit most often broken, including by the supervisor in RD-12:
+     the check `git grep "ActionState" -- apps/ssp/src/app/brief` cannot pass, because
+     `org-template.store.ts` lives in that directory and is deliberately out of scope until
+     RD-13. Name the files. If a command reaches a file the ticket says not to touch, one of
+     the two is wrong.
    - **Prefer a number over a prohibition for anything that must not change.** "Do not rename
      `BriefStatus`" invites reasoning around it; "this count must still be 54, and if it moves,
      revert rather than adjust the number" does not. RD-11 renamed tags across 19 files with a