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/shlex/shlex.ww

@@ -2,14 +2,6 @@
 // (ref/hare/shlex/{split.ha,escape.ha}) using ww byte-indexed cursors
 // in place of Hare's strings::iterator.
 //
-// Surface today:
-//
-//   shlex.syntaxerr            — !void; bad shell syntax
-//   shlex.strerror(syntaxerr)  — "Invalid shell syntax"
-//   shlex.split(in: str)       — tokenize; returns ([]str | syntaxerr)
-//   shlex.quote(io.stream, s)  — write `s` shell-quoted to a sink
-//   shlex.quotestr(s: str) str — quote into a fresh str
-//
 // Owning model: split() returns a fresh `[]str` of strings.dup'd
 // elements; release with [[strings.freeall]] (Hare's natural disposer
 // shape). quotestr() returns an os.alloc'd str; release via
@@ -227,7 +219,6 @@ export fn split(in: str) ([]str | syntaxerr) = {
 		dirty = true;
 
 		if (r == ' ' || r == '\t' || r == '\n') {
-			// Collapse a run of whitespace.
 			let inner: bool = true;
 			for (inner) {
 				if (pos >= in.len) { inner = false; }

lib/shlex/shlex_test.ww

@@ -1,6 +1,3 @@
-// shlextest — exercises lib/shlex. Run with
-// `out/bin/ww run lib/shlex/shlextest.ww`.
-//
 // Two cohorts, grouped Hare-style — one @test fn per cohort, table-
 // driven inside via per-arity helpers:
 //
@@ -110,8 +107,6 @@ fn checkquote(in: str, expected: str) void = {
 	let _c: (void | io.error) = io.close(snk);
 };
 
-// ---- split: Hare's @test fn split() table --------------------------
-//
 // 9 success rows + 3 syntaxerr rows ported VERBATIM from
 // ref/hare/shlex/+test.ha; plus one ww-specific edge (empty input →
 // empty []str) confirmed by drew.
@@ -146,8 +141,6 @@ fn checkquote(in: str, expected: str) void = {
 	checkempty("");
 };
 
-// ---- quote: Hare's testquote rows + the empty-input edge ----------
-//
 // 4 rows from ref/hare/shlex/+test.ha @test fn quote(). The empty-
 // input row (→ `''`) is implementation-specific (Hare's testquote
 // doesn't cover it) but is documented behaviour per shlex.ww's
@@ -163,16 +156,12 @@ fn checkquote(in: str, expected: str) void = {
 	checkquote("@%+=:,./-", "@%+=:,./-");
 };
 
-// ---- quotestr ------------------------------------------------------
-
 @test fn test_quotestr() void = {
 	let r: str = shlex.quotestr("hello world");
 	assert(!(!streq(r, "'hello world'")));
 	// leak r — short-lived test process, same precedent as fnmatchtest.
 };
 
-// ---- strerror ------------------------------------------------------
-
 @test fn test_strerror() void = {
 	let e: shlex.syntaxerr;
 	let s: str = shlex.strerror(e);