fix(js): clear interval handles when polling stops

Keep data-slhx-every timers separate from debounce/throttle timers and delete the interval handle when a polling element leaves the document, so reinserted elements can start polling again without leaking stale timer state.

req: convention/005

slhx-js/tests/runtime.rs

@@ -41,11 +41,14 @@ fn runtime_interval_dispatch_avoids_duplicate_timers() {
     // req: convention/005
     let source = slhx_js::RUNTIME_JS;
 
+    assert!(source.contains("const everyTimers = new WeakMap()"));
     assert!(source.contains("forEachElement(root, (el) =>"));
-    assert!(source.contains("!el.hasAttribute(\"data-slhx-every\") || timers.has(el)"));
-    assert!(source.contains("if (!el.hasAttribute(\"data-slhx-every\") || timers.has(el)) return"));
-    assert!(source.contains("setInterval(() => document.contains(el) ? send(el, \"every\")"));
-    assert!(source.contains("clearInterval(timers.get(el))"));
+    assert!(source.contains("!el.hasAttribute(\"data-slhx-every\") || everyTimers.has(el)"));
+    assert!(source.contains("if (!el.hasAttribute(\"data-slhx-every\") || everyTimers.has(el)) return"));
+    assert!(source.contains("setInterval(() => document.contains(el) ? send(el, \"every\") : stopPolling(el), ms)"));
+    assert!(source.contains("function stopPolling(el)"));
+    assert!(source.contains("clearInterval(everyTimers.get(el))"));
+    assert!(source.contains("everyTimers.delete(el)"));
 }
 
 #[test]