HS: collectionExpressions +4 (then on click, undefined where, component template)

- parser: nil return in parse-cmd for feature keywords (on/init/def/behavior/live)
  so "then on click" correctly hands off to outer coll-feats loop
- compiler: cek-try wrap for undefined variable refs in coll-where compilation
  so "doesNotExist where it > 1" returns nil instead of throwing
- integration: hs-activate! detects script[type=text/hyperscript-template] and
  applies handler to DOM instances via hs-query-all(component attr) not to script el

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

lib/hyperscript/integration.sx

@@ -115,7 +115,15 @@
             (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))
+            (let
+              ((handler (hs-handler src)))
+              (let
+                ((el-type (dom-get-attr el "type"))
+                  (comp-name (dom-get-attr el "component")))
+                (if
+                  (= el-type "text/hyperscript-template")
+                  (for-each handler (hs-query-all (or comp-name "")))
+                  (handler el))))
             (dom-dispatch el "hyperscript:after:init" nil)))))))
 
 ;; ── Boot subtree: for dynamic content ───────────────────────────