Adapter fixes, orchestration updates, example content + SPA tests

From other session: adapter-html/sx/dom fixes, orchestration
improvements, examples-content refactoring, SPA navigation test
updates, WASM copies synced.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shared/static/wasm/sx/adapter-sx.sx

@@ -66,7 +66,24 @@
             (= name "marsh")
             (aser-call name args env)
             (= name "error-boundary")
-            (aser-call name args env)
+            (let
+              ((has-fallback (> (len args) 1)))
+              (let
+                ((body-exprs (if has-fallback (rest args) args))
+                  (err-str nil))
+                (let
+                  ((rendered (try-catch (fn () (join "" (map (fn (x) (let ((v (aser x env))) (cond (= (type-of v) "sx-expr") (sx-expr-source v) (nil? v) "" :else (serialize v)))) body-exprs))) (fn (err) (set! err-str (str err)) nil))))
+                  (if
+                    rendered
+                    (make-sx-expr (str "(error-boundary " rendered ")"))
+                    (make-sx-expr
+                      (str
+                        "(div :data-sx-boundary \"true\" "
+                        "(div :class \"sx-render-error\" "
+                        ":style \"color:red;font-size:0.875rem;padding:0.5rem;border:1px solid red;border-radius:0.25rem;margin:0.5rem 0;\" "
+                        "\"Render error: "
+                        (replace (replace err-str "\"" "'") "\\" "\\\\")
+                        "\"))"))))))
             (contains? HTML_TAGS name)
             (aser-call name args env)
             (or (special-form? name) (ho-form? name))