Add js.sx bootstrapper docs page with G0 bug discovery writeup

Documents the self-hosting process for js.sx including the G0 bug
where Python's `if fn_expr` treated 0/False/"" as falsy, emitting
NIL instead of the correct value. Adds live verification page,
translation differences table, and nav entry.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sx/sxc/pages/docs.sx

@@ -459,6 +459,13 @@
           :g0-lines g0-lines
           :g0-bytes g0-bytes
           :verification-status verification-status)
+      "self-hosting-js"
+        (~bootstrapper-self-hosting-js-content
+          :js-sx-source js-sx-source
+          :defines-matched defines-matched
+          :defines-total defines-total
+          :js-sx-lines js-sx-lines
+          :verification-status verification-status)
       "python"
         (~bootstrapper-py-content
           :bootstrapper-source bootstrapper-source