Krypton Hybrid

Problem

Each non-empty light section (DataLayer) is always serialized as a raw 2048-byte * nibble array, regardless of content. Sky-light sections above the surface are nearly * always uniform (all nibble values == 15, stored as 0xFF bytes). In a standard * overworld chunk with a view distance of 12, up to 20 such "all-max" sections can be * present, costing {@code 20 × 2048 = 40 960} bytes of redundant light payload per chunk * before connection-level compression.

Solution – Uniform-RLE light encoding

When {@link KryptonConfig#lightOptEnabled} is {@code true} and net savings are * positive, the {@code write()} method is replaced with a Krypton-aware format * identified by a leading {@code 0x4B} ('K') marker byte:

 *   [0x4B]           – Krypton marker (1 byte)
 *   [trustEdges]     – boolean
 *   [skyYMask]       – BitSet (FriendlyByteBuf.writeBitSet)
 *   [blockYMask]     – BitSet
 *   [emptySkyYMask]  – BitSet
 *   [emptyBlockYMask]– BitSet
 *   [skyCount]       – VarInt
 *   For each sky DataLayer:
 *     [0x00] + 2048 bytes  – raw encoding (fixed size; no VarInt prefix)
 *     [0x01] + 1 byte      – uniform encoding (all nibble pairs == byte)
 *   [blockCount]     – VarInt
 *   For each block DataLayer: same as above
 *