Add MUDCraft Minecraft server infrastructure

- Purpur 1.21.4 server via itzg/docker-minecraft-server (java21)
- StatefulSet with 3 PVCs: worlds (20Gi), plugins (5Gi), logs (5Gi)
- Aikar G1GC JVM flags, 6GB heap (sized for Legion's 15GB RAM)
- Postgres: mudcraft database + user in existing platform/postgres
- RCON secret + DB password via ExternalSecret → Vault
- Traefik TCP entrypoint on port 25565 for mudcraft.nook.family
- mudcraft namespace via Terraform
- Argo CD app watching k8s/mudcraft/

servers/legion/k8s/mudcraft/configmap.yaml

@@ -0,0 +1,62 @@
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: mudcraft-config
+  namespace: mudcraft
+data:
+  # itzg/docker-minecraft-server env-based config
+  # These are injected as env vars — the entrypoint generates server.properties
+  TYPE: "PURPUR"
+  VERSION: "1.21.4"
+  DIFFICULTY: "hard"
+  MAX_PLAYERS: "40"
+  VIEW_DISTANCE: "8"
+  SIMULATION_DISTANCE: "6"
+  ALLOW_FLIGHT: "true"
+  ONLINE_MODE: "true"
+  SPAWN_PROTECTION: "0"
+  MAX_TICK_TIME: "-1"
+  RATE_LIMIT: "0"
+  ENFORCE_WHITELIST: "true"
+  WHITELIST_ENABLED: "true"
+  ENABLE_RCON: "true"
+  RCON_PORT: "25575"
+  MOTD: "MUDCraft — Private Beta"
+  MEMORY: ""  # Disabled — we set JVM flags directly
+  JVM_OPTS: >-
+    -Xms6G -Xmx6G
+    -XX:+UseG1GC
+    -XX:+ParallelRefProcEnabled
+    -XX:MaxGCPauseMillis=200
+    -XX:+UnlockExperimentalVMOptions
+    -XX:+DisableExplicitGC
+    -XX:+AlwaysPreTouch
+    -XX:G1NewSizePercent=30
+    -XX:G1MaxNewSizePercent=40
+    -XX:G1HeapRegionSize=8M
+    -XX:G1ReservePercent=20
+    -XX:G1HeapWastePercent=5
+    -XX:G1MixedGCCountTarget=4
+    -XX:InitiatingHeapOccupancyPercent=15
+    -XX:G1MixedGCLiveThresholdPercent=90
+    -XX:G1RSetUpdatingPauseTimePercent=5
+    -XX:SurvivorRatio=32
+    -XX:+PerfDisableSharedMem
+    -XX:MaxTenuringThreshold=1
+    -XX:+UseStringDeduplication
+    -Djava.awt.headless=true
+    -Dfile.encoding=UTF-8
+    -Dusing.aikars.flags=https://mcflags.emc.gs
+    -Daikars.new.flags=true
+  # Bukkit spawn limits — keep lower than default; MythicMobs adds custom mobs on top
+  OVERRIDE_BUKKIT_CONFIG: |
+    spawn-limits:
+      monsters: 40
+      animals: 8
+      water-animals: 3
+      water-ambient: 8
+      ambient: 4
+    ticks-per:
+      monster-spawns: 2
+      animal-spawns: 400