feat: Add first-launch server URL input dialog

Implements a setup dialog on first game launch that allows users to enter
their custom community server URL without rebuilding the APK.

Features:
- Server URL input dialog on first launch
- URL validation (format check)
- Connection test button
- SharedPreferences storage
- Priority: SharedPreferences > AndroidManifest.xml > EA defaults
- Activity restart flow for applying configuration

New files:
- CommunityServerManager.smali (URL management)
- ServerSetupActivity.smali + 4 inner classes (dialog UI)
- res/layout/activity_server_setup.xml (layout)
- SERVER-URL-INPUT-IMPLEMENTATION.md (docs)

Modified files:
- SynergyEnvironmentImpl.smali (SharedPreferences check priority)
- MainActivity.smali (first-launch check + onActivityResult)
- AndroidManifest.xml (declare ServerSetupActivity)

Benefits:
- One APK works with any server
- Easy server switching
- Lower barrier to entry for non-technical users

smali_classes2/com/firemint/realracing/ServerSetupActivity$2$1.smali

@@ -0,0 +1,107 @@
+.class Lcom/firemint/realracing/ServerSetupActivity$2$1;
+.super Ljava/lang/Object;
+.source "ServerSetupActivity.java"
+
+# interfaces
+.implements Ljava/lang/Runnable;
+
+
+# annotations
+.annotation system Ldalvik/annotation/EnclosingMethod;
+    value = Lcom/firemint/realracing/ServerSetupActivity$2;->run()V
+.end annotation
+
+.annotation system Ldalvik/annotation/InnerClass;
+    accessFlags = 0x0
+    name = null
+.end annotation
+
+
+# instance fields
+.field final synthetic this$1:Lcom/firemint/realracing/ServerSetupActivity$2;
+
+.field final synthetic val$success:Z
+
+
+# direct methods
+.method constructor <init>(Lcom/firemint/realracing/ServerSetupActivity$2;Z)V
+    .locals 0
+
+    .line 147
+    iput-object p1, p0, Lcom/firemint/realracing/ServerSetupActivity$2$1;->this$1:Lcom/firemint/realracing/ServerSetupActivity$2;
+
+    iput-boolean p2, p0, Lcom/firemint/realracing/ServerSetupActivity$2$1;->val$success:Z
+
+    invoke-direct {p0}, Ljava/lang/Object;-><init>()V
+
+    return-void
+.end method
+
+
+# virtual methods
+.method public run()V
+    .locals 2
+
+    .line 150
+    iget-boolean v0, p0, Lcom/firemint/realracing/ServerSetupActivity$2$1;->val$success:Z
+
+    if-eqz v0, :cond_0
+
+    .line 151
+    iget-object v0, p0, Lcom/firemint/realracing/ServerSetupActivity$2$1;->this$1:Lcom/firemint/realracing/ServerSetupActivity$2;
+
+    iget-object v0, v0, Lcom/firemint/realracing/ServerSetupActivity$2;->this$0:Lcom/firemint/realracing/ServerSetupActivity;
+
+    invoke-static {v0}, Lcom/firemint/realracing/ServerSetupActivity;->access$200(Lcom/firemint/realracing/ServerSetupActivity;)Landroid/widget/TextView;
+
+    move-result-object v0
+
+    const-string v1, "\u2705 Connection successful!"
+
+    invoke-virtual {v0, v1}, Landroid/widget/TextView;->setText(Ljava/lang/CharSequence;)V
+
+    .line 152
+    iget-object v0, p0, Lcom/firemint/realracing/ServerSetupActivity$2$1;->this$1:Lcom/firemint/realracing/ServerSetupActivity$2;
+
+    iget-object v0, v0, Lcom/firemint/realracing/ServerSetupActivity$2;->this$0:Lcom/firemint/realracing/ServerSetupActivity;
+
+    invoke-static {v0}, Lcom/firemint/realracing/ServerSetupActivity;->access$200(Lcom/firemint/realracing/ServerSetupActivity;)Landroid/widget/TextView;
+
+    move-result-object v0
+
+    const v1, -0xff6634
+
+    invoke-virtual {v0, v1}, Landroid/widget/TextView;->setTextColor(I)V
+
+    goto :goto_0
+
+    .line 154
+    :cond_0
+    iget-object v0, p0, Lcom/firemint/realracing/ServerSetupActivity$2$1;->this$1:Lcom/firemint/realracing/ServerSetupActivity$2;
+
+    iget-object v0, v0, Lcom/firemint/realracing/ServerSetupActivity$2;->this$0:Lcom/firemint/realracing/ServerSetupActivity;
+
+    invoke-static {v0}, Lcom/firemint/realracing/ServerSetupActivity;->access$200(Lcom/firemint/realracing/ServerSetupActivity;)Landroid/widget/TextView;
+
+    move-result-object v0
+
+    const-string v1, "\u274c Could not connect to server"
+
+    invoke-virtual {v0, v1}, Landroid/widget/TextView;->setText(Ljava/lang/CharSequence;)V
+
+    .line 155
+    iget-object v0, p0, Lcom/firemint/realracing/ServerSetupActivity$2$1;->this$1:Lcom/firemint/realracing/ServerSetupActivity$2;
+
+    iget-object v0, v0, Lcom/firemint/realracing/ServerSetupActivity$2;->this$0:Lcom/firemint/realracing/ServerSetupActivity;
+
+    invoke-static {v0}, Lcom/firemint/realracing/ServerSetupActivity;->access$200(Lcom/firemint/realracing/ServerSetupActivity;)Landroid/widget/TextView;
+
+    move-result-object v0
+
+    const/high16 v1, -0x10000
+
+    invoke-virtual {v0, v1}, Landroid/widget/TextView;->setTextColor(I)V
+
+    :goto_0
+    return-void
+.end method