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

selfhost/, cmd/, internal/ join the tree-wide sweep: every section
banner dies (91 selfhost + the cmd C-style dividers -> 0); narration
and stale contracts deleted (pre-#22 bundler notes, retired
single-PT_LOAD and no-archive claims, superseded ABI tables); every
ref/harec/qbe cite, task cite, encoding/ELF contract, and rule-10
twin pointer kept; lost lifetime/rationale lines restored where the
sweep over-cut (elf_globals ownership, kwtab linear-scan). Comment-
only proven: all five wwstage tool binaries byte-identical across
the sweep; test-commit, test-byteid (161+1399, 0 pinned-divergent),
and test-bootstrap (fixed point + 991-995 byte-id) all exit 0.
The read-through banked 66 latent-bug leads (checkpoint).

selfhost/cmd/w6l/main.ww

@@ -1,8 +1,4 @@
-// selfhost/cmd/w6l/main.ww — port of cmd/w6l/main.c.
-//
-// w6l = amd64 linker. Reads relocatable ELF .o files, SysV `ar`
-// archives, and shared objects (ET_DYN). Resolves symbols, applies
-// relocations, writes a static or dynamic-linked ELF executable.
+// Port of cmd/w6l/main.c.
 //
 //   w6l_ww -o out [-L<dir>...] [-l<name>...] file1.o file2.o ...
 
@@ -25,10 +21,6 @@ fn mklnk() *lnk = {
 	return l;
 };
 
-// `cstreq` lives in obj.ww — same bundle, single definition.
-
-// `cstrlen` lives in obj.ww — same bundle, single definition.
-
 // Build "<dir>/lib<name>.<ext>" into dst (NUL-terminated). Returns total
 // length excluding NUL. dst must be large enough.
 fn buildpath(dst: *u8, dir: *u8, name: *u8, ext: str) u64 = {
@@ -274,8 +266,7 @@ export fn main(argc: i32, argv: **u8) i32 = {
 		k += 1;
 	};
 
-	// Then resolve -l flags and load each. Archives append; shared
-	// objects register their exports.
+	// Archives append; shared objects register their exports.
 	let lf: i32 = 0;
 	for (lf < nlflags) {
 		let p: *u8 = resolvelib(lflags[lf], libdirs.ptr, nlibdirs);