JourneyMap TFC Integration

English

Adds TerraFirmaCraft rock layer, temperature, and precipitation overlays to the JourneyMap fullscreen map.

Overlay	Description
Rock Layers	Surface rock type color fill, 20 rock types supported
Temperature	-25°C ~ +40°C heatmap, blue → red
Precipitation	0 ~ 500mm heatmap, brown → blue

Data granularity: Overlay data is sampled at 3×3 chunk (48×48 block) resolution. The same data is shown for the entire 3×3 area, which may cause inaccuracies at rock/biome boundaries.
Viewport-based loading: toggling ON sends the current map viewport center to the server, which returns cached data within a 600-chunk radius to avoid excessive payload.
Cache persistence: explored area data is saved to <world>/data/jmtfc_cache.json on world save and automatically restored after restart. Cache is loaded at server startup (not on first client request) to prevent race conditions with other mods triggering saves.

./gradlew jar

Requires Java 21, Gradle 8.10+.

在 JourneyMap 全屏地图上叠加显示 TerraFirmaCraft 的岩层类型、温度和降水数据。

数据粒度：覆盖层以 3×3 chunk（48×48 方块）为最小采样单位。同一 3×3 区块内所有位置显示相同数据，区块边界处可能与实际地形有偏差。
视口请求：Toggle ON 时客户端向服务端发送当前地图视口中心，服务端返回半径 600 chunk 范围内的缓存数据，避免载荷过大。
缓存持久化：探索过的区域数据在存档时存入 <world>/data/jmtfc_cache.json，重启后自动恢复。缓存在服务端启动时即加载（不再依赖客户端首次请求），避免与其他模组的 save 事件产生竞争。

./gradlew jar

需要 Java 21、Gradle 8.10+。