sx-tools: WASM kernel updates, TW/CSSX rework, content refresh, new debugging tools

Build tooling: updated OCaml bootstrapper, compile-modules, bundle.sh, sx-build-all.
WASM browser: rebuilt sx_browser.bc.js/wasm, sx-platform-2.js, .sxbc bytecode files.
CSSX/Tailwind: reworked cssx.sx templates and tw-layout, added tw-type support.
Content: refreshed essays, plans, geography, reactive islands, docs, demos, handlers.
New tools: bisect_sxbc.sh, test-spa.js, render-trace.sx, morph playwright spec.
Tests: added test-match.sx, test-examples.sx, updated test-tw.sx and web tests.

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

shared/static/wasm/sx/boot-helpers.sx

@@ -430,17 +430,6 @@
         (host-callback thunk))
       (thunk))))
 
-(define
-  observe-intersection
-  (fn
-    (el callback once? delay)
-    (let
-      ((cb (host-callback (fn (entries) (for-each (fn (entry) (when (host-get entry "isIntersecting") (if delay (set-timeout (fn () (callback entry)) delay) (callback entry)) (when once? (host-call observer "unobserve" el)))) (host-call entries "forEach" (host-callback (fn (e) e))))))))
-      (let
-        ((observer (host-new "IntersectionObserver" (host-callback (fn (entries) (let ((arr-len (host-get entries "length"))) (let loop ((i 0)) (when (< i arr-len) (let ((entry (host-call entries "item" i))) (when (and entry (host-get entry "isIntersecting")) (if delay (set-timeout (fn () (callback entry)) delay) (callback entry)) (when once? (host-call observer "unobserve" el)))) (loop (+ i 1))))))))))
-        (host-call observer "observe" el)
-        observer))))
-
 (define
   event-source-connect
   (fn