fix(catalog): harden evaluators against correct-answer phrasing variance

Both reviewers found evaluators that scored correct answers as zero:
hardcoded flag order, quote-style rigidity, missing multiline anchors,
comma-grouped numbers, ratio notation, and numeric strings in JSON.
A shared ExactToken evaluator now normalizes fences, quotes, and
trailing periods for exact-answer tests. The obsolete tmutil snapshot
reference now accepts the current localsnapshot verb.

internal/tests/golang_test.go

@@ -479,6 +479,10 @@ func TestGoContextCancellationTraceTest_Eval(t *testing.T) {
 		{"exact correct", "context canceled", 1},
 		{"correct case-insensitive", "CONTEXT CANCELED", 1},
 		{"correct with surrounding whitespace", "  context canceled  ", 1},
+		// A7 regression: fenced/quoted decoration on the correct answer
+		// must still score full credit.
+		{"fenced", "```\ncontext canceled\n```", 1},
+		{"quoted with trailing period", `"context canceled".`, 1},
 		{"wrong: assumes select falls to default", "not done", 0},
 		{"wrong: wrong sentinel error", "context deadline exceeded", 0},
 	}