A Distinguished Lacunary Fibonacci Subset with Lie-Algebraic Scaling Identity

The six-element set Bit+ = {0, 1, 2, 3, 5, 8} is a lacunary extraction from the Fibonacci sequence, obtained by deduplicating F(1) = F(2) = 1 and truncating at F(6) = 8. We prove three results. First, Bit+ is characterized as a lacunary subset by the truncation at the smallest n for which F(n+1) exceeds twice the running sum (the Fibonacci overflow criterion). Second, the pairwise difference set of Bit+ achieves exactly twice the unique-baseline count of uniform spacing at the same cardinality (extremal non-redundancy). Third, the scaling identity 7 × Σ(Bit+) = 7 × 19 = 133 = dim(e7) holds, connecting the subset sum to the dimension of the exceptional Lie algebra e7 through the multiplier 7 = rank(E7). This identity is proved; it is not a conjecture.