Step 5p6 lazy loading + Step 6b VM transpilation prep

Lazy module loading (Step 5 piece 6 completion):
- Add define-library wrappers + import declarations to 13 source .sx files
- compile-modules.js generates module-manifest.json with dependency graph
- compile-modules.js strips define-library/import before bytecode compilation
  (VM doesn't handle these as special forms)
- sx-platform.js replaces hardcoded 24-file loadWebStack() with manifest-driven
  recursive loader — only downloads modules the page needs
- Result: 12 modules loaded (was 24), zero errors, zero warnings
- Fallback to full load if manifest missing

VM transpilation prep (Step 6b):
- Refactor lib/vm.sx: 20 accessor functions replace raw dict access
- Factor out collect-n-from-stack, collect-n-pairs, pad-n-nils helpers
- bootstrap_vm.py: transpiles 9 VM logic functions to OCaml
- sx_vm_ref.ml: proof that vm.sx transpiles (preamble has stubs)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shared/static/wasm/sx/highlight.sx

@@ -1,3 +1,22 @@
+
+
+(define-library (sx highlight)
+  (export
+    sx-specials
+    sx-special?
+    hl-digit?
+    hl-alpha?
+    hl-sym-char?
+    hl-ws?
+    hl-escape
+    hl-span
+    tokenize-sx
+    sx-token-classes
+    render-sx-tokens
+    highlight-sx
+    highlight)
+  (begin
+
 (define
   sx-specials
   (list
@@ -298,3 +317,9 @@
       (or (= lang "lisp") (= lang "sx") (= lang "sexp") (= lang "scheme"))
       (highlight-sx code)
       (list (quote code) code))))
+
+
+)) ;; end define-library
+
+;; Re-export to global namespace for backward compatibility
+(import (sx highlight))