fix: accept host:port in dictionary source URLs

URL validation rejected any host containing a colon, so sources on
non-standard ports could not be added. Strip the optional :port from
the host before applying the domain checks and validate the port
range (1-65535); the port is kept intact through template
normalization and URL building.

app/src/main/java/com/example/research/core/domain/model/DictionarySource.kt

@@ -132,8 +132,15 @@ data class DictionarySource(
                 val parts = afterProtocol.split("/")
                 if (parts.size < 2) return false
                 
-                val domain = parts[0]
+                val hostWithPort = parts[0]
-                if (domain.isEmpty()) return false
+                if (hostWithPort.isEmpty()) return false
+
+                val colonIndex = hostWithPort.lastIndexOf(':')
+                if (colonIndex >= 0) {
+                    val port = hostWithPort.substring(colonIndex + 1).toIntOrNull()
+                    if (port == null || port !in 1..65535) return false
+                }
+                val domain = if (colonIndex >= 0) hostWithPort.substring(0, colonIndex) else hostWithPort
                 if (domain != "localhost" && !domain.contains(".")) return false
                 
                 val filename = parts.last()