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/sx/specs.sx

@@ -293,8 +293,8 @@ boot.sx             depends on: cssx, orchestration, adapter-dom, render")))
           " spec files, runs the Python bootstrapper, and displays both the compiler source and its generated JavaScript output. "
           "The generated code below is live — it was produced by the bootstrapper at page load time, not served from a static file.")
         (p :class "text-xs text-stone-400 italic"
-          "The bootstrapped JavaScript is also injected as a script tag on this page. "
-          "Open the browser console to verify it loaded."))
+          "The sx-browser.js powering this page IS the bootstrapped output. "
+          "This page re-runs the bootstrapper to display the source and result."))
 
       (div :class "space-y-3"
         (div :class "flex items-baseline gap-3"
@@ -318,8 +318,7 @@ boot.sx             depends on: cssx, orchestration, adapter-dom, render")))
           "It is a complete, self-contained SX runtime — parser, evaluator, DOM adapter, engine, and CSS system.")
         (div :class "bg-stone-100 rounded-lg p-5 max-h-96 overflow-y-auto border border-violet-300"
           (pre :class "text-xs leading-relaxed whitespace-pre-wrap break-words"
-            (code (highlight bootstrapped-output "javascript"))))
-        (script :type "text/javascript" bootstrapped-output)))))
+            (code (highlight bootstrapped-output "javascript"))))))))
 
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