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/compiler.sx

@@ -2356,6 +2356,25 @@
                 ((= head (quote live-no-op)) nil)
                 ((= head (quote when-feat-no-op)) nil)
                 ((= head (quote bind-feat)) nil)
+                ((= head (quote socket))
+                  (let
+                    ((name-path (nth ast 1))
+                      (url (nth ast 2))
+                      (timeout (nth ast 3))
+                      (on-message (nth ast 4)))
+                    (let
+                      ((handler-sx (if (and (list? on-message) (= (first on-message) (quote on-message))) (list (quote fn) (list (quote event)) (hs-to-sx (nth on-message 2))) nil)))
+                      (let
+                        ((json? (if (and (list? on-message) (= (first on-message) (quote on-message))) (nth on-message 1) false)))
+                        (list
+                          (quote hs-socket-register!)
+                          (cons
+                            (quote list)
+                            (map (fn (seg) seg) name-path))
+                          (hs-to-sx url)
+                          (hs-to-sx timeout)
+                          handler-sx
+                          json?)))))
                 ((= head (quote on)) (emit-on ast))
                 ((= head (quote when-changes))
                   (let