fix: improve network connectivity and simplify proxy handling on JVM

- Set JVM DNS cache TTL to 30 seconds for positive lookups and 5 seconds for negative lookups to ensure network changes (like VPN toggles) are detected quickly.
- Refactor `createPlatformHttpClient` to simplify proxy configuration using OkHttp's native capabilities.
- Replace manual system proxy parsing with `proxySelector(ProxySelector.getDefault())` for `ProxyConfig.System`.
- Explicitly set `Proxy.NO_PROXY` when no proxy is configured.
- Remove redundant URI parsing and manual address mapping logic for system-level proxy detection.

Author: rainxchzed

composeApp/src/jvmMain/kotlin/zed/rainxch/githubstore/DesktopApp.kt

@@ -24,6 +24,12 @@ import java.awt.Desktop
 import kotlin.system.exitProcess
 
 fun main(args: Array<String>) {
+    // Reduce JVM DNS cache TTL so network changes (VPN on/off) are picked up quickly.
+    // Default JVM caches positive lookups for 30s and negative lookups forever,
+    // which breaks connectivity when a VPN changes DNS/routing mid-session.
+    java.security.Security.setProperty("networkaddress.cache.ttl", "30")
+    java.security.Security.setProperty("networkaddress.cache.negative.ttl", "5")
+
     initKoin()
 
     val deepLinkArg = args.firstOrNull()

core/data/src/jvmMain/kotlin/zed/rainxch/core/data/network/HttpClientFactory.jvm.kt

@@ -5,56 +5,32 @@ import io.ktor.client.engine.ProxyBuilder
 import io.ktor.client.engine.okhttp.OkHttp
 import io.ktor.http.Url
 import zed.rainxch.core.domain.model.ProxyConfig
+import java.net.Proxy
 import java.net.ProxySelector
-import java.net.URI
 
 actual fun createPlatformHttpClient(proxyConfig: ProxyConfig): HttpClient =
     HttpClient(OkHttp) {
         engine {
-            proxy =
-                when (proxyConfig) {
-                    is ProxyConfig.None -> {
-                        null
+            when (proxyConfig) {
+                is ProxyConfig.None -> {
+                    config {
+                        proxy(Proxy.NO_PROXY)
                     }
+                }
 
-                    is ProxyConfig.System -> {
-                        val systemProxy =
-                            ProxySelector
-                                .getDefault()
-                                ?.select(URI("https://api.github.com"))
-                                ?.firstOrNull { it.type() != java.net.Proxy.Type.DIRECT }
-
-                        if (systemProxy != null) {
-                            val addr = systemProxy.address() as? java.net.InetSocketAddress
-                            if (addr != null) {
-                                when (systemProxy.type()) {
-                                    java.net.Proxy.Type.HTTP -> {
-                                        ProxyBuilder.http(Url("http://${addr.hostString}:${addr.port}"))
-                                    }
-
-                                    java.net.Proxy.Type.SOCKS -> {
-                                        ProxyBuilder.socks(addr.hostString, addr.port)
-                                    }
-
-                                    else -> {
-                                        null
-                                    }
-                                }
-                            } else {
-                                null
-                            }
-                        } else {
-                            null
-                        }
+                is ProxyConfig.System -> {
+                    config {
+                        proxySelector(ProxySelector.getDefault())
                     }
+                }
 
-                    is ProxyConfig.Http -> {
-                        ProxyBuilder.http(Url("http://${proxyConfig.host}:${proxyConfig.port}"))
-                    }
+                is ProxyConfig.Http -> {
+                    proxy = ProxyBuilder.http(Url("http://${proxyConfig.host}:${proxyConfig.port}"))
+                }
 
-                    is ProxyConfig.Socks -> {
-                        ProxyBuilder.socks(proxyConfig.host, proxyConfig.port)
-                    }
+                is ProxyConfig.Socks -> {
+                    proxy = ProxyBuilder.socks(proxyConfig.host, proxyConfig.port)
                 }
+            }
         }
     }