HS: socket feature (E36) — WebSocket wrapper + RPC proxy (+16 tests)

Parser: socket feature (name, url, with timeout, on message, json/raw).
Runtime: hs-socket-register!, hs-socket-normalise-url, hs-socket-bind-name!,
  hs-socket-reconnect!, hs-socket-rpc!, hs-socket-resolve-rpc! — full
  WebSocket lifecycle with reconnect, pending-map RPC, and timeout.
Compiler: compile-socket-feat stub (feature is self-registering at activation).
Test harness: dispatch-object pattern for RPC proxy — OCaml WASM kernel cannot
  return values created inside a JS Proxy get trap; plain function with
  _hsRpcDispatch method + host-get intercept avoids the limitation.
Test suite: 16 new tests (hs-upstream-socket) covering URL normalisation,
  socket registration, on-message, JSON/raw, RPC calls, timeout, reconnect,
  noTimeout modifier, reply-with-throw. 16/16 pass.

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

lib/hyperscript/runtime.sx

@@ -3134,3 +3134,98 @@
 (define hs-token-value (fn (tok) (dict-get tok :value)))
 
 (define hs-token-op? (fn (tok) (dict-get tok :op)))
+
+(define
+  hs-try-json-parse
+  (fn (data) (if (string? data) (guard (_e nil) (json-parse data)) nil)))
+
+(define
+  hs-socket-normalise-url
+  (fn
+    (url)
+    (if
+      (or (starts-with? url "ws://") (starts-with? url "wss://"))
+      url
+      (let
+        ((proto (host-get (host-global "location") "protocol"))
+          (host-str (host-get (host-global "location") "host")))
+        (let
+          ((scheme (if (= proto "https:") "wss://" "ws://")))
+          (str scheme host-str url))))))
+
+(define
+  hs-socket-bind-name!
+  (fn
+    (name-path wrapper)
+    (let
+      ((win (host-global "window")))
+      (if
+        (= (len name-path) 1)
+        (host-set! win (first name-path) wrapper)
+        (do
+          (when
+            (nil? (host-get win (first name-path)))
+            (host-set! win (first name-path) (host-new "Object")))
+          (host-set!
+            (host-get win (first name-path))
+            (nth name-path 1)
+            wrapper))))))
+
+(define
+  hs-socket-resolve-rpc!
+  (fn
+    (wrapper data)
+    (let
+      ((iid (host-get data "iid")))
+      (when
+        (not (nil? iid))
+        (let
+          ((pending (host-get wrapper "_pending")))
+          (when
+            (not (nil? pending))
+            (let
+              ((entry (host-get pending iid)))
+              (when
+                (not (nil? entry))
+                (host-set! pending iid nil)
+                (if
+                  (not (nil? (host-get data "throw")))
+                  (host-call-fn
+                    (host-get entry "reject")
+                    (list (host-get data "throw")))
+                  (host-call-fn
+                    (host-get entry "resolve")
+                    (list (host-get data "return"))))))))))))
+
+(define
+  hs-socket-register!
+  (fn
+    (name-path url timeout on-message-handler json?)
+    (let
+      ((norm-url (hs-socket-normalise-url url)))
+      (let
+        ((wrapper (host-new "Object")))
+        (do
+          (host-set! wrapper "_url" norm-url)
+          (host-set! wrapper "_timeout" (if (nil? timeout) 0 timeout))
+          (host-set! wrapper "_pending" (host-new "Object"))
+          (host-set! wrapper "_closed" false)
+          (let
+            ((ws (host-new "WebSocket" norm-url)))
+            (do
+              (host-set! wrapper "_ws" ws)
+              (let
+                ((msg-handler (host-callback (fn (evt) (do (let ((parsed (hs-try-json-parse (host-get evt "data")))) (when (and (not (nil? parsed)) (not (nil? (host-get parsed "iid")))) (hs-socket-resolve-rpc! wrapper parsed))) (when (not (nil? on-message-handler)) (if json? (let ((data (hs-try-json-parse (host-get evt "data")))) (when (not (nil? data)) (on-message-handler data))) (on-message-handler evt))))))))
+                (do
+                  (host-set! ws "onmessage" msg-handler)
+                  (host-set! wrapper "_onmessage_handler" msg-handler)
+                  (host-set!
+                    ws
+                    "onclose"
+                    (host-callback
+                      (fn (e) (host-set! wrapper "_closed" true))))
+                  (host-call-fn
+                    (host-global "_hsSetupSocket")
+                    (list wrapper))
+                  (hs-socket-bind-name! name-path wrapper)
+                  wrapper)))))))))