lib: banner purge + WHY-only comment sweep (rule 8)

Every // ---- section banner dies (132 -> 0): names carry the WHAT.
Narration deleted (filename restatements, run-with lines, what-the-
next-line-does); every ref/hare cite, task cite, divergence, ABI/
layout contract, and ownership qualifier kept (borrowed-view lines
restored where the sweep over-cut). Comment-only proven: all 442
walk-workdir .s and 32 import-probe .s byte-identical before/after;
libbyteid 56-roster all-ID.

lib/hash/crc16/crc16.ww

@@ -1,5 +1,3 @@
-// hash/crc16 — CRC-16 checksum. Pure ww.
-//
 // Inline polynomial-shift per byte (no precomputed tables). Slower
 // than a table-driven CRC by ~8x per byte but matches the
 // table-driven answer bit-for-bit.
@@ -15,9 +13,7 @@ def ANSI: u16     = 0xA001u16;	// Modbus, USB, ANSI X3.28
 
 // sum16 — fold `buf` under `poly` and return ~cval. Initial value is
 // ~0u16, matching the streaming CRC-16 contract for a single
-// write-then-sum. Per byte: XOR low byte of cval with msg byte to form
-// an 8-bit index, run 8 polynomial shifts on that index, XOR the
-// result with the high byte of cval shifted down.
+// write-then-sum.
 export fn sum16(buf: []u8, poly: u16) u16 = {
 	let c: u16 = 0xFFFFu16;
 	let i: i32 = 0;