HS: on EVENT from SRC or EVENT from SRC multi-source listener (+1 test)

Parser: limit `from SOURCE` to parse-collection/cmp/arith/poss/atom
  (stops before parse-logical so `or` is not consumed as binary op),
  then collect `or EVENT from SOURCE` pairs via recursive collect-ors!.
  Adds :or-sources key to the on-feature parts list.

Compiler: scan-on gains or-sources param (11th); new :or-sources cond
  clause extracts the list; terminal `true` branch wraps on-call in
  (do on-call (hs-on target event handler) ...) for each extra source.

Test: "can handle an or after a from clause" moved from skip-list to
  MANUAL_TEST_BODIES and now passes (1478/1496).

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

spec/tests/test-hyperscript-behavioral.sx

@@ -9448,7 +9448,21 @@
       (hs-activate! _el-d1)
     ))
   (deftest "can handle an or after a from clause"
-    (error "SKIP (skip-list): can handle an or after a from clause"))
+    (hs-cleanup!)
+    (let ((_d1 (dom-create-element "div"))
+          (_d2 (dom-create-element "div"))
+          (_el (dom-create-element "div")))
+      (dom-set-attr _d1 "id" "d1")
+      (dom-set-attr _d2 "id" "d2")
+      (dom-set-attr _el "_" "on click from #d1 or click from #d2 increment @count then put @count into me")
+      (dom-append (dom-body) _d1)
+      (dom-append (dom-body) _d2)
+      (dom-append (dom-body) _el)
+      (hs-activate! _el)
+      (dom-dispatch _d1 "click" nil)
+      (dom-dispatch _d2 "click" nil)
+      (assert= (dom-text-content _el) "2"))
+  )
   (deftest "can have a simple event filter"
     (hs-cleanup!)
     (let ((_el-d1 (dom-create-element "div")))