Reactive island preservation across server-driven morphs

Islands survive hypermedia swaps: morph-node skips hydrated
data-sx-island elements when the same island exists in new content.
dispose-islands-in skips hydrated islands to prevent premature cleanup.

- @client directive: .sx files marked ;; @client send define forms to browser
- CSSX client-side: cssxgroup renamed (no hyphen) to avoid isRenderExpr
  matching it as a custom element — was producing [object HTMLElement]
- Island wrappers: div→span to avoid block-in-inline HTML parse breakage
- ~sx-header is now a defisland with inline reactive colour cycling
- bootstrap_js.py defaults output to shared/static/scripts/sx-browser.js
- Deleted stale sx-ref.js (sx-browser.js is the canonical browser build)
- Hegelian Synthesis essay: dialectic of hypertext and reactivity
- component-source helper handles Island types for docs pretty-printing

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

sx/sx/nav-data.sx

@@ -93,7 +93,9 @@
   (dict :label "Tools for Fools" :href "/essays/zero-tooling"
         :summary "SX was built without a code editor. No IDE, no build tools, no linters, no bundlers. What zero-tooling web development looks like.")
   (dict :label "React is Hypermedia" :href "/essays/react-is-hypermedia"
-        :summary "A React Island is a hypermedia control. Its behavior is specified in SX.")))
+        :summary "A React Island is a hypermedia control. Its behavior is specified in SX.")
+  (dict :label "The Hegelian Synthesis" :href "/essays/hegelian-synthesis"
+        :summary "On the dialectical resolution of the hypertext/reactive contradiction. Thesis: the server renders. Antithesis: the client reacts. Synthesis: the island in the lake.")))
 
 (define philosophy-nav-items (list
   (dict :label "The SX Manifesto" :href "/philosophy/sx-manifesto"
@@ -194,7 +196,11 @@
   (dict :label "sx-swarm" :href "/plans/sx-swarm"
         :summary "Container orchestration in SX — service definitions, environment macros, deploy pipelines. Replace YAML with a real language.")
   (dict :label "sx-proxy" :href "/plans/sx-proxy"
-        :summary "Reverse proxy in SX — routes, TLS, middleware chains, load balancing. Macros generate config from the same service definitions as the orchestrator.")))
+        :summary "Reverse proxy in SX — routes, TLS, middleware chains, load balancing. Macros generate config from the same service definitions as the orchestrator.")
+  (dict :label "Async Eval Convergence" :href "/plans/async-eval-convergence"
+        :summary "Eliminate hand-written evaluators — bootstrap async_eval.py from the spec via an async adapter layer. One spec, one truth, zero divergence.")
+  (dict :label "WASM Bytecode VM" :href "/plans/wasm-bytecode-vm"
+        :summary "Compile SX to bytecode, run in a Rust/WASM VM. Compact wire format, no parse overhead, near-native speed, DOM via JS bindings.")))
 
 (define reactive-islands-nav-items (list
   (dict :label "Overview" :href "/reactive-islands/"