Declare CB-WP-0021: import the edition, tier M

GROUND-WP-0002 T01 ruled the edition dataset authoritative, so the engine
must stop inventing Problem values and suits. Problems.csv carries 5
problems per scenario worth 2,2,2,3,3 (total 12) with a required_solution
each; the stand-in deals 3 worth 1,2,3 (total 6). GR-E01's thresholds of
5/7/9 are ordinary against 12 and unreachable against 6 -- which is why
the maintainer's last game ended 0 scores and winners nobody, and why
'GR-E01 unreachable below 5 seats' was carried as a rules gap. It was
never a rules gap.

Measured before declaring: AM-4a has 3,798 lines of headroom and a CSV
crate costs 21,613 marginal (csv 14,291 + csv-core 3,360 + ryu 3,962;
itoa/memchr/serde/serde_core are already present and free). 5.7x over, so
the shipped runtime cannot gain a CSV parser and that is settled by
measurement rather than preference.

The ADR's third question is the one that bites: Problem values and suits
become part of GroundState, which is hashed, so every recorded state hash
changes. A content import that quietly invalidates every hash in a
project whose central invariant is replay determinism is not a
data-loading change.

Chaos d8=7, no override.

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

workplans/CB-WP-0021-import-the-edition.md

@@ -0,0 +1,158 @@
+---
+id: CB-WP-0021
+kind: product
+title: "Import the edition: the game plays its own data"
+status: ready
+---
+
+# Purpose
+
+```
+structural tier  M   (adds or refuses an external dependency, and changes
+                      how a game is set up — a canonical interface)
+chaos            d8 = 7  → no override
+declared tier    M
+```
+
+Declaration 4 of chaos window 2.
+
+## The engine has been playing a stand-in
+
+`games/ground/src/lib.rs` builds Problems with `value: priority` and suits
+cycled by index. `editions/ground-darvo-r0/Problems.csv` has carried the
+real thing since 2026-07-31, and **GROUND-WP-0002 T01 ruled it
+authoritative on 2026-08-03**:
+
+| | problems/scenario | values | total | suits |
+|---|---:|---|---:|---|
+| `Problems.csv` | **5** | 2, 2, 2, 3, 3 | **12** | `required_solution` per problem |
+| the stand-in | 3 | 1, 2, 3 | **6** | cycled by index |
+
+GR-E01's thresholds are 2p → 5, 3–4p → 7, 5–6p → 9. **Ordinary against 12,
+unreachable against 6** — which is why the maintainer's last game ended
+`0` scores and `winners nobody`, and why clay-borg has been carrying
+`GR-E01 unreachable below 5 seats` as a rules gap for ground-game to rule
+on. It was never a rules gap.
+
+## The constraint, measured before declaring
+
+**AM-4a has 3,798 lines of headroom.** A CSV crate costs, marginally
+against the shipped graph:
+
+| crate | lines |
+|---|---:|
+| `csv` | 14,291 |
+| `csv-core` | 3,360 |
+| `ryu` | 3,962 |
+| **marginal total** | **21,613** |
+
+**5.7× the available headroom.** `itoa`, `memchr`, `serde` and
+`serde_core` are already present and cost nothing; the parser itself is
+what does not fit.
+
+So the shipped runtime cannot gain a CSV parser, and that is settled by
+measurement rather than by preference. What remains is *which* of the
+alternatives to take, and that is the ADR.
+
+## Task: decide how the data reaches the game
+
+```task
+id: CB-WP-0021-T01
+status: todo
+priority: high
+```
+
+Write `decisions/ADR-0011-*.md` (tier M: survey and decision in one).
+
+**Three questions, and the third is the one that bites.**
+
+**(a) Where does the data live?** `ground-game` is a separate repository.
+Depending on a sibling checkout makes the build depend on a path that may
+not exist; vendoring a copy makes clay-borg carry content it does not own.
+Whichever is chosen must say how a copy is known to be current, because a
+silently stale copy is worse than no copy.
+
+**(b) How is it parsed, given a CSV parser does not fit?** Candidates, and
+each needs its marginal cost stated rather than assumed:
+  - hand-rolled reader in `games/ground` — small, but it is a parser we
+    then own, and `problem_text` contains commas;
+  - **bake it**: a dev-time step converts the CSV into a generated Rust
+    module or compact literal, so the shipped runtime parses **nothing**.
+    Then the generated artifact must be proven to match its source, which
+    is the DFD class this repo already has machinery for;
+  - load nothing at runtime and treat the data as scenario input.
+
+**(c) What does this do to determinism?** Problem values and required
+suits become part of `GroundState`, which is hashed (K7). **Every recorded
+state hash changes.** Before writing code, establish what actually pins a
+hash today — `make sim` runs 25 scenarios, `replay-test` re-executes
+bundles, and AM-7's probe asserts per-segment hashes. Say which of those
+break, and whether any of them are *supposed* to be stable across a
+content change.
+
+**This is the reason the ADR exists.** A content import that quietly
+invalidates every recorded hash, in a project whose central invariant is
+replay determinism, is not a data-loading change.
+
+## Task: import it, and let the thresholds mean something
+
+```task
+id: CB-WP-0021-T02
+status: todo
+priority: high
+```
+
+Replace the stand-in. `setup` must build Problems from the edition data:
+`point_value`, `required_solution`, `visibility` (Surface → face up,
+Hidden → face down) and `hidden_priority`.
+
+**Controls:**
+- **The stand-in must become unreachable.** A test that the fixture
+  constants no longer appear — a `value: priority` that survives beside
+  real data is a fallback nobody will notice until the numbers look odd
+  again.
+- **A scenario must be able to reach GR-E01's threshold at 2 players**,
+  which is the specific thing that was impossible. Assert the arithmetic,
+  not just that a game runs.
+- The 5-problem shape must survive: the stand-in dealt 3, and code that
+  assumed 3 will not announce itself.
+
+## Task: retire the rules gap that was never one
+
+```task
+id: CB-WP-0021-T03
+status: todo
+priority: medium
+```
+
+`gr-e01-threshold-unreachable-2p` is tagged `provisional: true` with
+`provisional_owner: ground-game`, and its description says group success
+*"is unreachable at 2, 3 and 4 players"*. If T02 lands, that scenario is
+asserting a property of the **stand-in**, not of the game.
+
+Retire or rewrite it, and **say which of the six provisional items this
+resolves**, so GROUND-WP-0002 T03 shrinks rather than being left to
+rediscover it. Message `ground-game` with the outcome — the last such
+message sat unread for four days because nothing pointed at it.
+
+Do **not** quietly delete a failing-in-fact scenario. CB-EV-0005: *a score
+improved by deleting the question is not an improvement.*
+
+## Task: evidence
+
+```task
+id: CB-WP-0021-T04
+status: todo
+priority: high
+```
+
+`evidence/CB-EV-0019-*.md`.
+
+- **What the import cost**, against the 3,798 lines that were available.
+- **What broke**, especially hashes, and whether the blast radius was
+  predicted in T01 or discovered in T02. If it was discovered, say so —
+  that is the ADR having missed something.
+- **Whether the endings now mean anything**: play one and report the
+  score against the threshold.
+- **Quote CB-WP-0020's cost by re-running the instrument.**
+- **Chaos: 4 of 12 in window 2.**