feat: summoned minions enter the grid in Module 10 (a fourth seam; Clay Golem, Clay Shard)

Summoned records its summoner (the minion whose trigger is resolving) inside
the engine; the harness log is unchanged. When a Sequence ends, SpellGrid
writes spawned text, places each summoned minion with a noun on its
summoner's tile, removes the dead, reparses and syncs rule auras.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

course/10-spellgrid/reference/ts/tests/cli.test.ts

@@ -66,5 +66,5 @@ test("cli_numbers_are_plain_digits", () => {
   expect(cast.out).toContain('"Whirlwind -1 0" is not in the hand');
   // "+2" is not a number, so the chooser takes the first option.
   const graft = play("l2-spliced-corpse", ["c Graft", "+2", "1", "1", "q"]);
-  expect(graft.out).toContain("Hand: Ember Moth (Assembled)");
+  expect(graft.out).toContain("Hand: Clay Golem (Assembled)");
 });