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single-PT_LOAD and no-archive claims, superseded ABI tables); every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).

cmd/w6l/main.c

@@ -1,9 +1,4 @@
 /*
- * w6l — amd64 linker. Reads relocatable ELF .o files (from w6a) plus
- * .a archives, resolves, relocates, writes a static ELF executable.
- * Dynamic linking against .so files is the next increment; the -L/-l
- * flag plumbing here is its first step.
- *
  *   w6l -o out [-L<dir>...] [-l<name>...] file1.o file2.o ...
  *
  * The first symbol named "_start" defined among the inputs becomes
@@ -134,7 +129,6 @@ main(int argc, char **argv)
 	int rc = l_emit_elf(&l, f, base, base + 0x1000 + entry->val);
 	fclose(f);
 	if (rc == 0) {
-		/* chmod +x */
 		char cmd[1024];
 		snprintf(cmd, sizeof cmd, "chmod +x %s", out);
 		(void)system(cmd);