feat(dragonwilds): MATCH_PUBLIC so the join code works behind a relay

The server advertises the address its outgoing traffic comes from, so it
binds its public ports (-Port / -BeaconPort from {PUBLIC_PORT_n}) and, behind
Public Bypass, sends its traffic out through the relay. Adds portMode to the
schema and to import's field order.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MZxvxViV6QwAtVWT3saGvs

schema/game.schema.json

@@ -69,6 +69,10 @@
     "maxBackupSizeMb": { "type": ["integer", "null"], "minimum": 1 },
 
     "publicIpConfigKey": { "description": "Config key that receives the server's public address.", "type": ["string", "null"] },
+    "portMode": {
+      "description": "MATCH_PUBLIC: for games that advertise the address their own traffic comes from. The container binds the port players use (the relay port behind Public Bypass) and, behind a relay, all its outgoing traffic leaves through the relay. Tell the game its port with {PUBLIC_PORT_<defaultPort>} in defaultStartupCommand.",
+      "enum": ["DEFAULT", "MATCH_PUBLIC", null]
+    },
     "maxPlayersConfigKey": { "description": "Config key locked to the pricing tier's player count.", "type": ["string", "null"] },
     "mapConfigKey": { "type": ["string", "null"] },