T08 iter 1: scenario runner executes; GROUND setup and Select step

Replaces the RunOutcome::Unimplemented stub with a real runner:

- ScenarioGame trait: games own setup presets and the command
  vocabulary, the runner owns execution, assertions, and determinism.
- K8 double-run: every scenario runs twice on the same seed and fails
  on state-hash divergence.
- K4/K11: applied events go through Envelope into EventLog, so seq
  monotonicity is enforced on the real path, not just in unit tests.
- setup.patch was parsed and silently dropped; the runner now applies
  it generically and errors on a path that does not exist, so a typo
  in a scenario can never pass as a no-op.
- Assertions: dot-path state lookup over objects and arrays, ordered
  event subsequence matching by field subset, exact rejects-set match.

GROUND rules realized: GR-S01..S04 setup (seeded shuffle, deal, Lead,
Surface Problem face up), GR-R02 Select commit, GR-R03 stress gate and
Freedom spend, GR-A13 targeting legality.

cb-sim dispatches by the scenario's game prefix and reports rule
coverage. 3 scenarios pass, 7 rules covered; fmt/clippy/tests green.

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

crates/cb-game-runtime/src/lib.rs

@@ -3,7 +3,7 @@
 
 pub mod scenario;
 
-pub use scenario::{RunOutcome, ScenarioFile};
+pub use scenario::{parse_actor, run, CommandStep, RunOutcome, ScenarioFile, ScenarioGame, Setup};
 
 use cb_kernel::PlayerId;
 use serde::{Deserialize, Serialize};