style: remove every em-dash and en-dash

Eighteen occurrences across fourteen files. Each sentence was repunctuated to
suit what the dash was doing rather than swapped for a hyphen, which produces
comma splices. The minus sign in folio-web's ledger is a minus sign and stays.

Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX

internal/ltl/evaluator_test.go

@@ -45,9 +45,9 @@ func TestThunk_TransitionFromHoldToViolate(t *testing.T) {
 	wantSequence := []Verdict{
 		VerdictHolds,    // true
 		VerdictHolds,    // true
-		VerdictViolated, // false — latches
-		VerdictViolated, // true after violation — still violated
-		VerdictViolated, // true after violation — still violated
+		VerdictViolated, // false: latches
+		VerdictViolated, // true after violation: still violated
+		VerdictViolated, // true after violation: still violated
 	}
 	for index, want := range wantSequence {
 		got := evaluator.Observe()