SXC content: docs/examples/home/reference pages + SX testing runner

New sxc/ content tree with 120 page files across docs, examples, home,
and reference demos. sx/sx/testing/ adds page-runner.sx (317L) and
index-runner.sx (394L) — SX-native test runner pages for
browser-based evaluation.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

sx/sxc/examples/pp-view.sx

@@ -0,0 +1,16 @@
+(defcomp
+  (&key name email role)
+  (div
+    (~tw :tokens "space-y-3")
+    (div
+      (~tw :tokens "flex justify-between items-start")
+      (div
+        (p (~tw :tokens "text-stone-800 font-medium") name)
+        (p (~tw :tokens "text-sm text-stone-500") email)
+        (p (~tw :tokens "text-sm text-stone-500") role))
+      (button
+        :sx-get "/sx/(geography.(hypermedia.(example.(api.putpatch-edit-all))))"
+        :sx-target "#pp-target"
+        :sx-swap "innerHTML"
+        (~tw :tokens "text-sm text-violet-600 hover:text-violet-800")
+        "Edit All (PUT)"))))