Fix Shardok to default to localhost for local development (#4807)

The previous change defaulted to 0.0.0.0:40042 which broke local
development - Shardok would bind to the network IP instead of localhost,
causing Eagle to fail to connect.

- Default to localhost:40042 for local development
- Docker sets SHARDOK_EAGLE_INTERFACE_ADDRESS=0.0.0.0:40042 to listen
  on all interfaces for container networking

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

docker-compose.prod.yml

@@ -46,6 +46,7 @@ services:
     environment:
       SHARDOK_RESOURCES_PATH: "/app/resources"
       SHARDOK_MAPS_PATH: "/app/resources/maps"
+      SHARDOK_EAGLE_INTERFACE_ADDRESS: "0.0.0.0:40042"
     restart: unless-stopped
     logging:
       driver: "json-file"

src/main/cpp/net/eagle0/shardok/server/ServerConfiguration.cpp

@@ -32,13 +32,15 @@ unordered_map<string, string> DefaultValues();
 
 unordered_map<string, string> DefaultValues() {
     // Check environment variables for Docker deployment
+    // Docker containers should set SHARDOK_EAGLE_INTERFACE_ADDRESS=0.0.0.0:40042
+    // to listen on all interfaces for container networking
     const char* eagleInterfaceAddr = getenv("SHARDOK_EAGLE_INTERFACE_ADDRESS");
     const char* shardokAddr = getenv("SHARDOK_GRPC_ADDRESS");
 
     return unordered_map<string, string>{
             {ServerConfiguration::kShardokGrpcAddress, shardokAddr ? shardokAddr : "localhost"},
             {ServerConfiguration::kEagleInterfaceGrpcAddress,
-             eagleInterfaceAddr ? eagleInterfaceAddr : "0.0.0.0:40042"}};
+             eagleInterfaceAddr ? eagleInterfaceAddr : "localhost:40042"}};
 }
 
 ServerConfiguration::ServerConfiguration(const string& filePath) {