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/strings/dup_test.ww

@@ -27,7 +27,6 @@ import os;
 	defer os.free(m.ptr: *void, m.len: u64);
 };
 
-// ---- dupall -----------------------------------------------------------
 // ref/hare/strings/dup.ha:55 (#6). Element reads go through
 // `&toks.ptr[i]: *str`
 // per the splitn cases (16B element copy gap, cgen.c:6515).
@@ -109,4 +108,3 @@ import os;
 	case nomem => { abort(); };
 	};
 };
-