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/strconv/int_test.ww

@@ -1,6 +1,3 @@
-// inttest — exercises lib/strconv integer parse: parseint / stoi64 /
-// stou64 / the iN/uN width wrappers.
-//
 // Verbatim port of ref/hare/strconv/stoi.ha:56-86 (stoi/stoi_bases) and
 // stou.ha:116-138 (stou/stou_bases). Hare's strconv integer tests are
 // flat assert SEQUENCES, not row-array tables — mirrored here as inline
@@ -210,7 +207,6 @@ fn ck_uint_ovf(id: i32, s: str, b: base) void = {
 	ck_uint(62, "110101", base.BIN, 53u64: uint);        // 0b110101
 };
 
-// ---- format side: u64tos / i64tos / machine-word wrappers ------------
 // Verbatim ports of ref/hare/strconv/utos.ha:74-103 (utos/utos_bases) and
 // itos.ha:54-87 (itos/itos_bases) — Hare's format tests are flat assert
 // sequences too. Radix-literal inputs are written in DECIMAL (ww value