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/parser.sx

@@ -3178,6 +3178,35 @@
                   (match-kw "end")
                   (list (quote bind-feat) lhs rhs)))
               (true (do (match-kw "end") (list (quote bind-feat) lhs nil)))))))
+      (define
+        parse-socket-feat
+        (fn
+          ()
+          (let
+            ((first-seg (tp-val)))
+            (do
+              (adv!)
+              (define
+                collect-dots!
+                (fn
+                  (acc)
+                  (if
+                    (= (tp-type) "class")
+                    (let
+                      ((seg (tp-val)))
+                      (do (adv!) (collect-dots! (append acc (list seg)))))
+                    acc)))
+              (let
+                ((name-path (collect-dots! (list first-seg))))
+                (let
+                  ((url (parse-arith (parse-poss (parse-atom)))))
+                  (let
+                    ((timeout (if (match-kw "with") (do (when (and (or (= (tp-type) "ident") (= (tp-type) "keyword")) (= (tp-val) "timeout")) (adv!)) (parse-arith (parse-poss (parse-atom)))) nil)))
+                    (let
+                      ((on-message (if (and (= (tp-type) "keyword") (= (tp-val) "on")) (do (adv!) (when (and (or (= (tp-type) "ident") (= (tp-type) "keyword")) (= (tp-val) "message")) (do (adv!) (let ((json? (if (match-kw "as") (do (when (and (or (= (tp-type) "ident") (= (tp-type) "keyword")) (= (tp-val) "JSON")) (adv!)) true) false))) (let ((body (parse-cmd-list))) (list (quote on-message) json? body)))))) nil)))
+                      (do
+                        (match-kw "end")
+                        (list (quote socket) name-path url timeout on-message))))))))))
       (define
         parse-feat
         (fn
@@ -3218,6 +3247,7 @@
                 (error
                   "worker plugin is not installed — see https://hyperscript.org/features/worker"))
               ((= val "bind") (do (adv!) (parse-bind-feat)))
+              ((= val "socket") (do (adv!) (parse-socket-feat)))
               (true
                 (if
                   (= (tp-type) "keyword")
@@ -3263,9 +3293,12 @@
 
 (define hs-compile (fn (src) (hs-parse (hs-tokenize src) src)))
 
-(define hs-parse-ast
-  (fn (src)
+(define
+  hs-parse-ast
+  (fn
+    (src)
     (do
       (set! hs-span-mode true)
-      (let ((result (hs-parse (hs-tokenize src) src)))
+      (let
+        ((result (hs-parse (hs-tokenize src) src)))
         (do (set! hs-span-mode false) result)))))