docs: use git grep for acceptance checks, and fix RD-09's ledger row

Four acceptance commands in this backlog could not pass as written. The
fourth, in RD-09, reached this backlog's own ticket files and 22
gitignored worktrees, so satisfying it literally would have rewritten the
history of completed tickets.

The general fix is `git grep` instead of `grep -r`: it searches tracked
files only, so untracked and gitignored paths cannot pollute the result.
Measured here, `grep -r` finds 132 hits under .claude/ where `git grep`
finds none. RD-17, RD-18 and RD-19 are repo-wide sweeps and depend on
this.

Also correct RD-09's Order row. It claimed the ticket covered a generator
and a skill file; neither teaches the deleted idiom, as recorded in
PLAN.md.

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

docs/project/readable-codebase/README.md

@@ -103,7 +103,7 @@ two. Note that RD-15 exists because 22 abandoned agent worktrees are still on di
 | RD-06 | **Bug fix:** 2 single-step forms to the effect map + retry affordance        | 05         | yes       | done   |
 | RD-07 | Add `Primary` to the 3 wizard machines + specs                               | 05         |           | done   |
 | RD-08 | Migrate the 3 wizards to the effect map + `Primary`                          | 07         | yes       | done   |
-| RD-09 | **Docs + generator:** `form-machine.hbs`, ARCHITECTURE, fp-tea, skill        | 08         |           | done   |
+| RD-09 | Teach the effect map: ARCHITECTURE §2d + fp-tea (2 docs, no generator)       | 08         |           | done   |
 | RD-10 | `WizardStatus` to a payload-carrying `WizardPhase`                           | 08         | yes       | todo   |
 | RD-11 | Fold the lifecycle projection into `remote-data.ts`; PascalCase 3 machines   | 01         |           | todo   |
 | RD-12 | `ActionState` becomes `action` on `BriefState.Loaded`                        | 11         |           | todo   |
@@ -180,7 +180,7 @@ Three rules when you write a ticket file, because the agent reads its ticket and
    estimate and nothing can check it. `npm run lint` has an exit code.
 4. **Run every acceptance command against the tree before you hand the ticket over.** A
    command that cannot pass is worse than no command: the agent either wastes a cycle or,
-   worse, "fixes" correct code to satisfy it. Three real misses so far, all in tickets written
+   worse, "fixes" correct code to satisfy it. Four real misses so far, all in tickets written
    by the supervisor:
    - RD-06 grepped only `runIfSubmitting`, missing that one wizard spells it `runIfIndienen`.
    - RD-08 grepped bare `onPrimary\|onRetry`, which can never return nothing — an unrelated
@@ -188,6 +188,18 @@ Three rules when you write a ticket file, because the agent reads its ticket and
    - RD-08 said "no machine changes" while also requiring a repo-wide grep to come back
      clean, which forced comment edits in three machines. The two instructions contradicted
      each other.
+   - RD-09 grepped `docs/ apps/ libs/ .claude/`, which also matched this backlog's own ticket
+     files (they name the deleted method as the history of `done` work) and 22 gitignored
+     abandoned worktrees. Satisfying it literally would have corrupted completed-ticket
+     history.
 
-   Anchor greps on a declaration (`^  onRetry\(\)`) rather than a name, and make the Files
-   list agree with the Acceptance commands.
+   Three habits that prevent all four:
+
+   - **Use `git grep`, not `grep -r`.** It searches tracked files only, so untracked and
+     gitignored paths never pollute the result. Measured on this repo: `grep -r` finds 132
+     hits under `.claude/`, `git grep` finds 0. This matters most for RD-17, RD-18 and RD-19,
+     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.