HS: hyperscript:before:init / :after:init events (+2 tests)

integration.sx hs-activate! now wraps the activation block in a cancelable
hyperscript:before:init event (dispatched on the el via dom-dispatch which
returns the dispatchEvent boolean — true unless preventDefault was called).
On success it dispatches hyperscript:after:init at the end. Both events
bubble so listeners on a containing wa work-area receive them. Generator
gets two hand-rolled deftests that exercise the new dispatch via
hs-boot-subtree!: one captures both events into a list, the other
preventDefaults before:init and asserts data-hyperscript-powered is absent.

hs-upstream-core/bootstrap: 20/26 → 22/26. Smoke 0-195: 170 → 172.

Remaining 4 cluster-29 tests need stricter parser error-rejection
(hs-upstream-core/parser, parse-error event); larger than a single
cluster budget — leave as untranslated for now.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

shared/static/wasm/sx/hs-integration.sx

@@ -80,11 +80,14 @@
       ((src (dom-get-attr el "_")) (prev (dom-get-data el "hs-script")))
       (when
         (and src (not (= src prev)))
-        (hs-log-event! "hyperscript:init")
-        (dom-set-data el "hs-script" src)
-        (dom-set-data el "hs-active" true)
-        (dom-set-attr el "data-hyperscript-powered" "true")
-        (let ((handler (hs-handler src))) (handler el))))))
+        (when
+          (dom-dispatch el "hyperscript:before:init" nil)
+          (hs-log-event! "hyperscript:init")
+          (dom-set-data el "hs-script" src)
+          (dom-set-data el "hs-active" true)
+          (dom-set-attr el "data-hyperscript-powered" "true")
+          (let ((handler (hs-handler src))) (handler el))
+          (dom-dispatch el "hyperscript:after:init" nil))))))
 
 ;; ── Boot: scan entire document ──────────────────────────────────
 ;; Called once at page load. Finds all elements with _ attribute,