VM import suspension for browser lazy loading

Bytecode compiler now emits OP_PERFORM for (import ...) and compiles
(define-library ...) bodies. The VM stores the import request in
globals["__io_request"] and stops the run loop — no exceptions needed.
vm-execute-module returns a suspension dict, vm-resume-module continues.

Browser: sx_browser.ml detects suspension dicts from execute_module and
returns JS {suspended, op, request, resume} objects. The sx-platform.js
while loop handles cascading suspensions via handleImportSuspension.

13 modules load via .sxbc bytecode in 226ms (manifest-driven), both
islands hydrate, all handlers wired. 2650/2650 tests pass including
6 new vm-import-suspension tests.

Also: consolidated sx-platform-2.js → sx-platform.js, fixed
vm-execute-module missing code-from-value call, fixed bootstrap.py
protocol registry transpiler issues.

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

shared/sx/helpers.py

@@ -884,7 +884,7 @@ def _get_shell_static() -> dict[str, Any]:
         sx_css=sx_css,
         sx_css_classes=sx_css_classes,
         wasm_hash=_wasm_hash("sx_browser.bc.wasm.js"),
-        platform_hash=_wasm_hash("sx-platform-2.js"),
+        platform_hash=_wasm_hash("sx-platform.js"),
         sxbc_hash=_sxbc_hash(),
         asset_url=_ca.config.get("ASSET_URL", "/static"),
         inline_css=_shell_cfg.get("inline_css"),
@@ -1035,7 +1035,7 @@ def sx_page_streaming_parts(ctx: dict, page_html: str, *,
     pages_sx = _build_pages_sx(current_app.name)
 
     wasm_hash = _wasm_hash("sx_browser.bc.wasm.js")
-    platform_hash = _wasm_hash("sx-platform-2.js")
+    platform_hash = _wasm_hash("sx-platform.js")
     sxbc_hash = _sxbc_hash()
 
     # Shell: head + body with server-rendered HTML (not SX mount script)
@@ -1078,7 +1078,7 @@ def sx_page_streaming_parts(ctx: dict, page_html: str, *,
     tail = (
         _SX_STREAMING_BOOTSTRAP + '\n'
         + f'<script src="{asset_url}/wasm/sx_browser.bc.wasm.js?v={wasm_hash}"></script>\n'
-          f'<script src="{asset_url}/wasm/sx-platform-2.js?v={platform_hash}" data-sxbc-hash="{sxbc_hash}"></script>\n'
+          f'<script src="{asset_url}/wasm/sx-platform.js?v={platform_hash}" data-sxbc-hash="{sxbc_hash}"></script>\n'
     )
 
     return shell, tail

shared/sx/templates/shell.sx

@@ -81,5 +81,5 @@
               "/wasm/sx_browser.bc.wasm.js?v="
               (or wasm-hash "0")))
           (script
-            :src (str asset-url "/wasm/sx-platform-2.js?v=" (or platform-hash "0"))
+            :src (str asset-url "/wasm/sx-platform.js?v=" (or platform-hash "0"))
             :data-sxbc-hash (or sxbc-hash "0")))))))