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{

tests/playwright/generate-sx-tests.py

@@ -1894,6 +1894,40 @@ def generate_eval_only_test(test, idx):
             f'    (assert (nil? (eval-hs "cookies.foo"))))'
         )
 
+    # Special case: cluster-36 socket URL tests. These check URL normalisation
+    # by running the socket feature with a mock WebSocket and asserting the
+    # URL passed to the constructor.
+    if test['name'] in (
+        'converts relative URL to ws:// on http pages',
+        'converts relative URL to wss:// on https pages',
+        'parses socket with absolute ws:// URL',
+    ):
+        https_mode = 'wss' in test['name']
+        if test['name'] == 'parses socket with absolute ws:// URL':
+            hs_src = 'socket MySocket ws://localhost:1234/ws end'
+            expected_url = 'ws://localhost:1234/ws'
+            proto_setup = ''
+            proto_restore = ''
+        else:
+            hs_src = 'socket RelSocket /my-ws end'
+            expected_url = 'wss://localhost/my-ws' if https_mode else 'ws://localhost/my-ws'
+            if https_mode:
+                proto_setup = '    (host-set! (host-global "location") "protocol" "https:")\n'
+                proto_restore = '    (host-set! (host-global "location") "protocol" "http:")\n'
+            else:
+                proto_setup = ''
+                proto_restore = ''
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (host-set! (host-global "window") "__hs_ws_created" (list))\n'
+            + proto_setup +
+            f'    (eval-hs "{hs_src}")\n'
+            + proto_restore +
+            f'    (let ((sock (host-get (host-global "__hs_ws_created") 0)))\n'
+            f'      (assert= (host-get sock "url") "{expected_url}")))' 
+        )
+
     # Special case: cluster-29 init events. The two tractable tests both attach
     # listeners to a wa container, set its innerHTML to a hyperscript fragment,
     # then call `_hyperscript.processNode(wa)`. Hand-roll deftests using