CB-WP-0008-T01: bots — the kernel's first non-scenario consumer

A Policy trait, a seeded random policy and a greedy one with a stated
heuristic, a legal-command generator that filters candidates through
validate, and a driver that runs a 3-player all-bot game to GameEnded.
Same-seed runs are hash-identical (K8), and a different policy seed
produces a different game — without that second assertion the first is
satisfied by a bot that ignores its RNG.

Every failure is loud, because the one a bot driver must not have is the
silent one: no legal move, passing where an action is required, an
out-of-range index (not clamped), a rejected command, and a stall guard.

What the second consumer found, none of it fixed here:
- GR-A13 admits SOLVE against an already-claimed Problem and resolution
  then does nothing — the action is silently wasted. The policy avoids
  it; the rule is left for a ruling.
- The 3-player standard fixture cannot reach GR-E01's threshold of 7:
  three Problems valued 1,2,3 cap the total at 6. No scenario noticed
  because none plays to scoring.
- K13's Project trait still has zero implementors. T02 is its first.

Mutation-checked by hand. The first mutation was a no-op and survived;
removing the Resolve call outright turned three tests red for the stated
reason. Third instance of the weak-mutation class.

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

history/260801-cb-wp-0008-log.md

@@ -0,0 +1,64 @@
+# 2026-08-01 — CB-WP-0008 delivery notes
+
+Kept out of the workplan file so it stays loadable (`loop-lint`).
+
+## T01 — bots
+
+`games/ground/src/bot.rs`, 8 tests. `Policy` + `RandomPolicy` (seeded
+`ChaChaRng`) + `GreedyPolicy` (stated heuristic, deterministic), a
+`legal_commands` generator that filters candidates through `validate`, and
+a driver that reaches `GameEnded`.
+
+Measured, 3-player, seed 42, both policies to GR-R09's fifth round:
+
+| policy | commands | events | claimed | total vs threshold |
+|---|---|---|---|---|
+| random | 36 | 81 | 1 | 2 / 7 |
+| greedy | 30 | 51 | 2 | 3 / 7 |
+
+**The module is not gated on `scenarios`; its tests are.** A bot needs
+only the aggregate, but the setup presets live behind that feature. That
+is a real seam and it is left visible rather than papered over with a
+feature the bot does not need.
+
+### What the second consumer found
+
+INTENT's second-use rule is why T01 was worth doing before the CLI. Three
+findings, none of them fixed here, because fixing a rule from inside a bot
+is exactly the invention-in-isolation the rule guards against.
+
+1. **GR-A13 admits SOLVE against an already-claimed Problem.** The rule
+   names "a face-up, non-Denied Problem"; `claimed_by` is not mentioned,
+   so `check_targeting` accepts it and resolution then does nothing. The
+   action is silently wasted. Greedy hit this immediately — it spent all
+   fifteen selections re-solving Problem 1 and scored 1. The **policy**
+   now avoids it; the **rule** is untouched and this is a U-item
+   candidate for GroundRules.
+
+2. **The 3-player standard fixture cannot succeed.** GR-S01 gives 3
+   Problems at 3–4 players, the preset values them by priority (1, 2, 3 —
+   maximum 6), and GR-E01 sets the 3–4p threshold at **7**.
+   `group_success` is therefore unreachable at 3 players regardless of
+   play. No scenario noticed because no scenario plays to scoring with
+   maximal claiming. The fixture is documented as placeholder ("Problem
+   content is scenario data") — so this is evidence that the placeholder
+   is not neutral, not that GR-E01 is wrong.
+
+3. **K13's `Project` trait has zero implementors.** `grep` finds no
+   `impl Project` anywhere in the tree. T02 is its first consumer, and
+   the projection will be written against a trait that has never been
+   exercised.
+
+### Process
+
+The acceptance tests were mutation-checked by hand (no `mutation-check`
+row — that denominator is the GameKernel acceptance table, and adding a
+game-level row would move a metric by changing its question).
+
+**The first mutation was a no-op and SURVIVED**: it changed
+`apply(...)?` to `let _ = apply(...)`, which still issues the command.
+Removing the `Resolve` call outright turned three tests red for their
+stated reason. Third recorded instance of the weak-mutation class — the
+retrospective in `260801-instrument-the-table-retrospective.md` predicted
+mutation strength would stay a standing maintenance cost, and this is
+that cost arriving on the next pass.