HS E36: socket URL parsing + hs-socket-register! runtime (+3 tests)

- parser.sx: parse-socket-feat handles /path and scheme:// URLs; collect-url
  greedily joins URL continuation tokens (ident/number/op/colon/dot)
- tokenizer.sx: fix :// not treated as line comment (lookback check)
- compiler.sx: emit-socket compiles socket AST to hs-socket-register! call
- runtime.sx: hs-socket-register! normalises URL (relative→ws:/wss:),
  constructs WebSocket, builds wrapper dict, binds on window name-path
- hs-run-filtered.js: WebSocket mock uses plain object (not JS array) so
  host-global returns a foreign value rather than SX list; host-get idx works

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

tests/hs-run-filtered.js

@@ -534,7 +534,10 @@ globalThis.getSelection=()=>({toString:()=>(globalThis.__test_selection||'')});
 // HsWebSocket — cluster-36 WebSocket mock. Records every constructed socket
 // in globalThis.__hs_ws_created so tests can assert on URLs and sent frames.
 // Tests may override globalThis.WebSocket before activating hyperscript.
-globalThis.__hs_ws_created = [];
+// __hs_ws_created is a plain object with numeric keys (NOT a JS array).
+// JS arrays are auto-converted to SX lists by host-global; plain objects stay foreign.
+// host-get foreign 0  →  foreign[0]  →  mock sock  ✓
+globalThis.__hs_ws_created = {_len: 0};
 globalThis.WebSocket = function HsWebSocket(url) {
   const sock = {
     url,
@@ -546,7 +549,11 @@ globalThis.WebSocket = function HsWebSocket(url) {
     removeEventListener(t, h) { const a = sock._listeners[t]; if (a) { const i = a.indexOf(h); if (i >= 0) a.splice(i, 1); } },
     close() { (sock._listeners['close'] || []).forEach(h => { try { h({}); } catch(_) {} }); }
   };
-  globalThis.__hs_ws_created.push(sock);
+  // If the test reset __hs_ws_created to a SX list (via host-set! ... (list)), reinitialise.
+  if (typeof globalThis.__hs_ws_created?._len !== 'number') globalThis.__hs_ws_created = {_len: 0};
+  const idx = globalThis.__hs_ws_created._len;
+  globalThis.__hs_ws_created[idx] = sock;
+  globalThis.__hs_ws_created._len++;
   return sock;
 };
 // _hs_make_rpc_proxy — cluster-36 RPC proxy factory. Called by the runtime
@@ -746,7 +753,8 @@ for(let i=startTest;i<Math.min(endTest,testCount);i++){
   try{
     // Use SX-level guard to catch errors, avoiding __sxR side-channel issues
     // Returns a dict with :ok and :error keys
-    K.eval(`(define _test-result (_run-test-thunk (get (nth _test-registry ${i}) "thunk")))`);
+    const _dbgR=K.eval(`(define _test-result (_run-test-thunk (get (nth _test-registry ${i}) "thunk")))`);
+    if(suite==='hs-upstream-socket'&&i<=1292)process.stderr.write(`[D] i=${i} r=${JSON.stringify(_dbgR)?.slice(0,100)}\n`);
     const isOk=K.eval('(get _test-result "ok")');
     if(isOk===true){ok=true;}
     else{