Fix reactive islands client-side navigation and hydration

Three bugs prevented islands from working during SX wire navigation:

1. components_for_request() only bundled Component and Macro defs, not
   Island defs — client never received defisland definitions during
   navigation (components_for_page for initial HTML shell was correct).

2. hydrate-island used morph-children which can't transfer addEventListener
   event handlers from freshly rendered DOM to existing nodes. Changed to
   clear+append so reactive DOM with live signal subscriptions is inserted
   directly.

3. asyncRenderToDom (client-side async page eval) checked _component but
   not _island on ~-prefixed names — islands fell through to generic eval
   which failed. Now delegates to renderDomIsland.

4. setInterval_/setTimeout_ passed SX Lambda objects directly to native
   timers. JS coerced them to "[object Object]" and tried to eval as code,
   causing "missing ] after element list". Added _wrapSxFn to convert SX
   lambdas to JS functions before passing to timers.

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

shared/sx/ref/render.sx

@@ -190,6 +190,30 @@
       local)))
 
 
+;; --------------------------------------------------------------------------
+;; is-render-expr? — check if expression is a rendering form
+;; --------------------------------------------------------------------------
+;; Used by eval-list to dispatch rendering forms to the active adapter
+;; (HTML, SX wire, or DOM) rather than evaluating them as function calls.
+
+(define is-render-expr?
+  (fn (expr)
+    (if (or (not (= (type-of expr) "list")) (empty? expr))
+      false
+      (let ((h (first expr)))
+        (if (not (= (type-of h) "symbol"))
+          false
+          (let ((n (symbol-name h)))
+            (or (= n "<>")
+                (= n "raw!")
+                (starts-with? n "~")
+                (starts-with? n "html:")
+                (contains? HTML_TAGS n)
+                (and (> (index-of n "-") 0)
+                     (> (len expr) 1)
+                     (= (type-of (nth expr 1)) "keyword")))))))))
+
+
 ;; --------------------------------------------------------------------------
 ;; Platform interface (shared across adapters)
 ;; --------------------------------------------------------------------------
@@ -199,11 +223,6 @@
 ;;   (escape-attr s)           → attribute-value-escaped string
 ;;   (raw-html-content r)      → unwrap RawHTML marker to string
 ;;
-;; Serialization:
-;;   (serialize val)           → SX source string representation of val
-;;
-;; Form classification (used by SX wire adapter):
-;;   (special-form? name)      → boolean
-;;   (ho-form? name)           → boolean
-;;   (aser-special name expr env) → evaluate special/HO form through aser
+;; From parser.sx:
+;;   (sx-serialize val)        → SX source string (aliased as serialize above)
 ;; --------------------------------------------------------------------------