getVectorUint8

Read a Vector<N, Uint<8>> losslessly. Each element comes from Compact's runtime as BigInteger; we narrow to Int with a 0..255 range check per element. List length must equal expectedLength — mismatch indicates schema drift; throws.

The runtime-driven path preserves zero-element positions (a Uint<8>=0 serializes to 0 bytes in the cell, so manual cell-hex parsing would lose its index — this accessor queries via queryLedgerState per element instead).