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

@@ -24,6 +24,29 @@ test("cli_wins_level_2_with_choices_and_play", () => {
   expect(out).toContain("Hand: Ember Moth (Assembled)");
 });
 
+test("cli_prints_the_log_tree_of_each_command", () => {
+  const { out } = play("l1-double-tap", ["w", "w", "c Whirlwind", "q"]);
+  // The moves run no Sequence, so only the cast prints a log: its tree, Deathrattles nested.
+  expect(out.split("Log:\n")).toHaveLength(2);
+  expect(out).toContain(
+    [
+      "Log:",
+      'SpellCast{card: "Whirlwind"}',
+      "Damaged{target: 32, amount: 1}",
+      "Damaged{target: 33, amount: 1}",
+      "Destroyed{id: 32}",
+      "DeathPhase{round: 1}",
+      'Triggered{source: 32, trigger: "deathrattle"}',
+      "  Damaged{target: 33, amount: 1}",
+      'Triggered{source: 32, trigger: "deathrattle"}',
+      "  Damaged{target: 33, amount: 1}",
+      "Destroyed{id: 33}",
+      "DeathPhase{round: 2}",
+      "",
+    ].join("\n"),
+  );
+});
+
 test("cli_reports_errors_and_quits", () => {
   const { outcome, out } = play("l3-simultaneous-paradox", ["c Spark", "x", "q"]);
   expect(outcome).toBe("quit");