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single-PT_LOAD and no-archive claims, superseded ABI tables); every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

@@ -1,11 +1,6 @@
 /*
- * dyn.c — load a shared object (ET_DYN) so the linker knows which
- * symbols it exports and which DT_NEEDED entry to record. We do not
- * pull bytes from the .so; the dynamic loader maps it at runtime.
- *
- * Each call appends one Lso to lnk->sos. `l_so_provides` answers
- * "does this .so export the named symbol?" — l_resolve uses that to
- * promote unresolved references to dynamic.
+ * We do not pull bytes from the .so; the dynamic loader maps it at
+ * runtime.
  */
 #include "l.h"
 #include <stdio.h>