HS E36: RPC timeout tests (10, 11, 14) — 16/16 complete

All 16 socket tests now green.

Fake synchronous setTimeout queue (__hsFlushTimers) lets the synchronous
test harness drive RPC timeout tests without real async waiting:
- default timeout: flush timers → wrapper.pending emptied (rejected)
- noTimeout: flush timers → wrapper.pending still has entry (not rejected)
- timeout(n): flush timers → 50ms timer fires → pending emptied

_rpcDispatch handles "noTimeout"/"timeout" method names, returning
new proxy or timeout-factory function respectively.

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

tests/hs-run-filtered.js

@@ -18,6 +18,28 @@ const K = globalThis.SxKernel;
 // awaits RPC promises; rejections from timed-out or unresolved calls are expected.
 process.on('unhandledRejection', () => {});
 
+// ─── Fake timer (for RPC timeout tests) ────────────────────────────────────
+// socket timeout tests need setTimeout to fire synchronously on demand.
+// Replace global setTimeout with a queue; __hsFlushTimers fires all pending.
+let _fakeTimers = [];
+let _fakeTimerIdCtr = 0;
+const _realSetTimeout = globalThis.setTimeout;
+globalThis.setTimeout = function(cb, _delay) {
+  const id = ++_fakeTimerIdCtr;
+  _fakeTimers.push({ id, cb });
+  return id;
+};
+globalThis.clearTimeout = function(id) {
+  const idx = _fakeTimers.findIndex(t => t.id === id);
+  if (idx >= 0) _fakeTimers.splice(idx, 1);
+};
+// __hsFlushTimers — drain all pending timers synchronously.
+// Exposed as a plain object so host-call o "call" works.
+globalThis.__hsFlushTimers = { call: function() {
+  const batch = _fakeTimers.splice(0);
+  for (const { cb } of batch) { try { cb(); } catch (_) {} }
+}};
+
 // Step limit API — exposed from OCaml kernel
 const STEP_LIMIT = parseInt(process.env.HS_STEP_LIMIT || '200000');
 
@@ -760,6 +782,7 @@ for(let i=startTest;i<Math.min(endTest,testCount);i++){
   globalThis.__hsMutationRegistry.length = 0;
   globalThis.__hsMutationActive = false;
   globalThis.__currentHsTestName = name;
+  _fakeTimers = []; // reset timer queue between tests
 
   // Enable step limit for timeout protection
   setStepLimit(STEP_LIMIT);

tests/playwright/generate-sx-tests.py

@@ -2096,6 +2096,65 @@ def generate_eval_only_test(test, idx):
             f'          (assert= (host-get (host-global "__hs_ws_created") "_len") 2)))))'
         )
 
+    # Test 10: rpc proxy default timeout rejects the promise.
+    # With a socket created using `with timeout 50`, calling rpc.neverReplies()
+    # enqueues a fake setTimeout. After flushing timers, wrapper.pending should
+    # be empty (the timeout callback deleted the entry and rejected the promise).
+    if test['name'] == 'rpc proxy default timeout rejects the promise':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (eval-hs "socket DefTOSocket ws://localhost/ws with timeout 50 end")\n'
+            f'    (let ((wrapper (host-get (host-global "window") "DefTOSocket")))\n'
+            f'      (let ((rpc (host-get wrapper "rpc")))\n'
+            f'        (do\n'
+            f'          (host-call rpc "neverReplies")\n'
+            f'          (let ((keys-before (host-call (host-global "Object") "keys" (host-get wrapper "pending"))))\n'
+            f'            (assert= (host-get keys-before "length") 1))\n'
+            f'          (host-call (host-global "__hsFlushTimers") "call")\n'
+            f'          (let ((keys-after (host-call (host-global "Object") "keys" (host-get wrapper "pending"))))\n'
+            f'            (assert= (host-get keys-after "length") 0))))))'
+        )
+
+    # Test 11: rpc proxy noTimeout avoids timeout rejection.
+    # rpc.noTimeout returns a proxy with timeout=Infinity; no setTimeout is
+    # registered so flushing timers leaves the pending entry intact.
+    if test['name'] == 'rpc proxy noTimeout avoids timeout rejection':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (eval-hs "socket NoTOSocket ws://localhost/ws with timeout 20 end")\n'
+            f'    (let ((wrapper (host-get (host-global "window") "NoTOSocket")))\n'
+            f'      (let ((rpc (host-get wrapper "rpc")))\n'
+            f'        (do\n'
+            f'          (let ((no-timeout (host-call rpc "noTimeout")))\n'
+            f'            (host-call no-timeout "slowCall" "x"))\n'
+            f'          (host-call (host-global "__hsFlushTimers") "call")\n'
+            f'          (let ((keys-after (host-call (host-global "Object") "keys" (host-get wrapper "pending"))))\n'
+            f'            (assert= (host-get keys-after "length") 1))))))'
+        )
+
+    # Test 14: rpc proxy timeout(n) rejects after a custom window.
+    # rpc.timeout(50) returns a proxy with overrideTimeout=50; calling a method
+    # on it enqueues a 50ms fake timer. After flushing, pending is empty.
+    if test['name'] == 'rpc proxy timeout(n) rejects after a custom window':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (eval-hs "socket CustomTOSocket ws://localhost/ws with timeout 60000 end")\n'
+            f'    (let ((wrapper (host-get (host-global "window") "CustomTOSocket")))\n'
+            f'      (let ((rpc (host-get wrapper "rpc")))\n'
+            f'        (do\n'
+            f'          (let ((timeout-fn (host-call rpc "timeout"))\n'
+            f'                (custom-proxy (host-call-fn timeout-fn (list 50))))\n'
+            f'            (host-call custom-proxy "willTimeOut"))\n'
+            f'          (let ((keys-before (host-call (host-global "Object") "keys" (host-get wrapper "pending"))))\n'
+            f'            (assert= (host-get keys-before "length") 1))\n'
+            f'          (host-call (host-global "__hsFlushTimers") "call")\n'
+            f'          (let ((keys-after (host-call (host-global "Object") "keys" (host-get wrapper "pending"))))\n'
+            f'            (assert= (host-get keys-after "length") 0))))))'
+        )
+
     # 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