feat: log tree from Module 2 (logTree / log_tree); SpellGrid CLIs print Log:

Engine events carry the nesting depth they were recorded at; the harness
prints the log as an indented tree. New tests test_02_log_tree_shows_nesting
and test_03_log_tree_death_phase; both SpellGrid CLIs print the tree of the
last command's Sequences under a Log: line.

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

course/02-action-queue/tests/ts/test_02.test.ts

@@ -71,6 +71,29 @@ test("test_02_depth_first_nesting", () => {
   expect(g.health(g.hero(1))).toBe(29);
 });
 
+test("test_02_log_tree_shows_nesting", () => {
+  const g = newGame();
+  const e = g.summon("Test Echo", 0);
+  const s = g.summon("Armorsmith", 0);
+  const r = g.summon("Test Reactor", 0);
+  const enemy = g.hero(1);
+  g.clearLog();
+
+  g.dealDamage(s, 1);
+
+  expect(g.logTree()).toBe(
+    [
+      `Damaged{target: ${s}, amount: 1}`,
+      `Triggered{source: ${e}, trigger: "damaged"}`,
+      `  Damaged{target: ${enemy}, amount: 1}`,
+      `  Triggered{source: ${r}, trigger: "damaged"}`,
+      `    StatsChanged{id: ${r}, attack: 2, health: 5}`,
+      `Triggered{source: ${s}, trigger: "damaged"}`,
+      `  ArmorGained{player: 0, amount: 1}`,
+    ].join("\n") + "\n",
+  );
+});
+
 test("test_02_empty_deck_draw_is_fatigue", () => {
   const g = newGame();
   const a = g.summon("Acolyte of Pain", 0);