Update reference docs: fix event names, add demos, document sx-boost target

- Remove sx:afterSettle (not dispatched), rename sx:sendError → sx:requestError
- Add sx:clientRoute event (Phase 3 client-side routing)
- Add working demos for all 10 events (afterRequest, afterSwap, requestError,
  clientRoute, sseOpen, sseMessage, sseError were missing demos)
- Update sx-boost docs: configurable target selector, client routing behavior
- Remove app-specific nav logic from orchestration.sx, use sx:clientRoute event
- Pass page content deps to sx_response for component loading after server fallback

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

sx/sx/reference.sx

@@ -20,6 +20,10 @@
 
 (defcomp ~reference-events-content (&key table)
   (~doc-page :title "Events"
+    (p :class "text-stone-600 mb-6"
+      "sx fires custom DOM events at various points in the request lifecycle. "
+      "Listen for them with sx-on:* attributes or addEventListener. "
+      "Client-side routing fires sx:clientRoute instead of request lifecycle events.")
     table))
 
 (defcomp ~reference-js-api-content (&key table)