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single-PT_LOAD and no-archive claims, superseded ABI tables); every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/wwdump/main.c

@@ -1,10 +1,7 @@
 /*
- * wwdump — deterministic dump tool for ww source.
- *
- * Reads a .ww file and writes either a token stream or an AST
- * s-expression to stdout, byte-for-byte stable across runs. It is the
- * diff anchor for self-host: the C-side libwcc and the future ww-side
- * frontend must produce the same dump for the same input.
+ * Diff anchor for self-host: the C-side libwcc and the future ww-side
+ * frontend must produce the same dump for the same input, byte-for-byte
+ * stable across runs.
  *
  *   wwdump -t file.ww   tokens, one per line: "<file>:<l>:<c> <kind> [val]"
  *   wwdump -a file.ww   AST as s-expr, one node per line
@@ -70,7 +67,7 @@ dump_ast(const char *src, char *buf, u64 len, FILE *out)
 int
 main(int argc, char **argv)
 {
-	int mode = 't';	/* tokens by default */
+	int mode = 't';
 	const char *src = NULL;
 	const char *out = NULL;
 	for (int i = 1; i < argc; i++) {