Add header and event detail pages, fix copyright, rename essay

- Detail pages for all 18 HTTP headers with descriptions, example usage,
  direction badges (request/response/both), and live demos for SX-Prompt,
  SX-Trigger, SX-Retarget
- Detail pages for all 10 DOM events with descriptions, example usage,
  and live demos for beforeRequest, afterSettle, responseError,
  validationFailed
- Header and event table rows now link to their detail pages
- Fix copyright symbol on home page (was literal \u00a9, now actual ©)
- Rename "Godel, Escher, Bach" essay to "Strange Loops" with updated summary
- Remove duplicate script injection from bootstrapper page

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

sx/sxc/pages/docs.sx

@@ -115,6 +115,43 @@
       :handler-code attr-handler
       :wire-placeholder-id attr-wire-id)))
 
+(defpage reference-header-detail
+  :path "/reference/headers/<slug>"
+  :auth :public
+  :layout (:sx-section
+    :section "Reference"
+    :sub-label "Reference"
+    :sub-href "/reference/"
+    :sub-nav (~section-nav :items reference-nav-items :current "Headers")
+    :selected "Headers")
+  :data (header-detail-data slug)
+  :content (if header-not-found
+    (~reference-attr-not-found :slug slug)
+    (~reference-header-detail-content
+      :title header-title
+      :direction header-direction
+      :description header-description
+      :example-code header-example
+      :demo header-demo)))
+
+(defpage reference-event-detail
+  :path "/reference/events/<slug>"
+  :auth :public
+  :layout (:sx-section
+    :section "Reference"
+    :sub-label "Reference"
+    :sub-href "/reference/"
+    :sub-nav (~section-nav :items reference-nav-items :current "Events")
+    :selected "Events")
+  :data (event-detail-data slug)
+  :content (if event-not-found
+    (~reference-attr-not-found :slug slug)
+    (~reference-event-detail-content
+      :title event-title
+      :description event-description
+      :example-code event-example
+      :demo event-demo)))
+
 ;; ---------------------------------------------------------------------------
 ;; Protocols section
 ;; ---------------------------------------------------------------------------