nx_zstd_lit_gate.nx

nx_zstd_lit_gate.nx -- proves the zstd literals section. T2 pins the NON-BYTE-ALIGNED size fields. Two bits of block type and two of size format share byte 0 with the TOP of the regenerated size, so every size read starts at bit 4 and runs on little-endian. Reading whole bytes instead yields a value wrong by a factor of 16 -- loud on a large block, silent on a small one. The test uses hand-built headers at every size format and asserts the decoded size exactly. T3 pins the DOUBLE MEANING of the format field. For Raw and RLE, formats 0 and 2 are the SAME one-byte form. For Compressed and Treeless the same two values mean different things -- 0 is ONE stream, 1 is FOUR, both with 10-bit sizes. One field, two interpretations, decided by the block type. T5 decodes Huffman literals end-to-end through the table built by nx_zstd_huf: header -> table -> backward stream -> literal bytes. It reuses the hand-assembled stream whose symbol sequence is derived in the huf gate, so the expected output is known independently of this code. license_tier: ORIGINAL