fix(compose): remove server.properties-aliased env vars so UI edits persist

The itzg/minecraft-bedrock-server entrypoint rewrites server.properties
from env vars on every start. Any property edited via mc-manager's UI was
being clobbered because those env vars were set here. Remove them so
/data/server.properties (on the named volume) is the real source of truth:

  - SERVER_NAME, GAMEMODE, DIFFICULTY, ALLOW_CHEATS, ONLINE_MODE,
    MAX_PLAYERS, DEFAULT_PLAYER_PERMISSION_LEVEL
  - LEVEL_SEED (jamie) — world already generated
  - LEVEL_NAME — moved to docker-compose.override.yml, managed by
    mc-manager so UI Set Active survives future deploys

Kept: EULA, SERVER_PORT (deploy-time wiring), OP_PERMISSION_LEVEL
(not a server.properties key).

Override file is gitignored so mc-manager's writes don't leak into git.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -4,16 +4,13 @@ services:
     container_name: mc-lobby
     environment:
       EULA: "TRUE"
-      SERVER_NAME: "SilverLABS Hub"
-      GAMEMODE: adventure
-      DIFFICULTY: peaceful
-      ALLOW_CHEATS: "true"
-      ONLINE_MODE: "false"
       SERVER_PORT: "19132"
-      LEVEL_NAME: "Hub World"
-      MAX_PLAYERS: "10"
-      DEFAULT_PLAYER_PERMISSION_LEVEL: operator
       OP_PERMISSION_LEVEL: "4"
+      # Other server.properties-aliased env vars (SERVER_NAME, GAMEMODE, DIFFICULTY,
+      # ALLOW_CHEATS, ONLINE_MODE, MAX_PLAYERS, DEFAULT_PLAYER_PERMISSION_LEVEL) are
+      # intentionally not set here — they're owned by /data/server.properties inside
+      # the named volume and edited via mc-manager's UI. LEVEL_NAME lives in
+      # docker-compose.override.yml on the host (managed by mc-manager, gitignored).
     ports:
       - "${LOBBY_PORT:-19132}:19132/udp"
     volumes:
@@ -44,17 +41,10 @@ services:
     container_name: mc-jamie
     environment:
       EULA: "TRUE"
-      SERVER_NAME: "Jamie's World"
-      GAMEMODE: survival
-      DIFFICULTY: normal
-      ALLOW_CHEATS: "true"
-      ONLINE_MODE: "false"
       SERVER_PORT: "19132"
-      LEVEL_NAME: "Jamie World"
-      LEVEL_SEED: "-6717666844935858147"
-      MAX_PLAYERS: "10"
-      DEFAULT_PLAYER_PERMISSION_LEVEL: operator
       OP_PERMISSION_LEVEL: "4"
+      # See lobby for rationale. LEVEL_SEED is dropped too — the world has long since
+      # been generated and the seed is ignored thereafter.
     ports:
       - "${JAMIE_PORT:-19133}:19132/udp"
     volumes:
@@ -78,15 +68,7 @@ services:
     container_name: mc-lyla
     environment:
       EULA: "TRUE"
-      SERVER_NAME: "Lyla's World"
-      GAMEMODE: survival
-      DIFFICULTY: normal
-      ALLOW_CHEATS: "true"
-      ONLINE_MODE: "false"
       SERVER_PORT: "19132"
-      LEVEL_NAME: "Lyla World"
-      MAX_PLAYERS: "10"
-      DEFAULT_PLAYER_PERMISSION_LEVEL: operator
       OP_PERMISSION_LEVEL: "4"
     ports:
       - "${LYLA_PORT:-19134}:19132/udp"
@@ -119,15 +101,7 @@ services:
     container_name: mc-mya
     environment:
       EULA: "TRUE"
-      SERVER_NAME: "Mya's World"
-      GAMEMODE: survival
-      DIFFICULTY: normal
-      ALLOW_CHEATS: "true"
-      ONLINE_MODE: "false"
       SERVER_PORT: "19132"
-      LEVEL_NAME: "Mya World"
-      MAX_PLAYERS: "10"
-      DEFAULT_PLAYER_PERMISSION_LEVEL: operator
       OP_PERMISSION_LEVEL: "4"
     ports:
       - "${MYA_PORT:-19135}:19132/udp"