Add event bindings and data-sx-emit processing

- adapter-dom.sx: detect :on-click/:on-submit etc. in render-dom-element
  — if attr starts with "on-" and value is callable, wire via dom-listen
- orchestration.sx: add process-emit-elements for data-sx-emit attrs
  — auto-dispatch custom events on click with optional JSON detail
- bootstrap_js.py: add processEmitElements RENAME
- Regenerate sx-ref.js with all changes
- Update reactive-islands status table

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

shared/sx/ref/bootstrap_js.py

@@ -397,6 +397,7 @@ class JSEmitter:
             "bind-sse": "bindSse",
             "bind-sse-swap": "bindSseSwap",
             "bind-inline-handlers": "bindInlineHandlers",
+            "process-emit-elements": "processEmitElements",
             "bind-preload-for": "bindPreloadFor",
             "do-preload": "doPreload",
             "VERB_SELECTOR": "VERB_SELECTOR",