fix(demo): normalize bare-domain URLs for consistent behavior

normalizeUrl now appends trailing slash to bare-domain URLs
(e.g. https://example.com → https://example.com/) to match browser
normalization behavior. This ensures manual URL entry and programmatic
navigation behave consistently across platforms.

Author: kdroidFilter

demo-shared/src/commonMain/kotlin/io/github/kdroidfilter/webview/demo/DemoUtils.kt

@@ -3,9 +3,22 @@ package io.github.kdroidfilter.webview.demo
 internal fun normalizeUrl(raw: String): String {
     val trimmed = raw.trim()
     if (trimmed.isEmpty()) return "about:blank"
-    if (trimmed.startsWith("http://") || trimmed.startsWith("https://")) return trimmed
     if (trimmed.startsWith("file://")) return trimmed
-    return "https://$trimmed"
+
+    val url = if (trimmed.startsWith("http://") || trimmed.startsWith("https://")) {
+        trimmed
+    } else {
+        "https://$trimmed"
+    }
+
+    // Add trailing slash for bare-domain URLs (e.g. https://example.com → https://example.com/)
+    // to match browser normalization behavior
+    val schemeEnd = url.indexOf("://") + 3
+    val pathStart = url.indexOf('/', schemeEnd)
+    if (pathStart == -1 && url.indexOf('?', schemeEnd) == -1 && url.indexOf('#', schemeEnd) == -1) {
+        return "$url/"
+    }
+    return url
 }
 
 internal fun hostFromUrl(url: String): String? {