Fix Dynmap area markers always rendering at y=64

[Copilot]

Dynmap defaults ytop/ybottom to 64 when setRangeY is never called, causing all island area markers to appear at sea level regardless of world height — visually wrong in isometric view.

Changes

• DynmapHook.setMarker() — calls area.setRangeY(world.getMaxHeight(), world.getMinHeight()) after creating the internal island area marker, spanning the full world height range (e.g. -64 → 320 for the overworld)
• DynmapHook.addPolygonMarker() — same fix applied to the public MapHook API path; covers addAreaMarker() since it delegates here

AreaMarker area = markerSet.createAreaMarker(...);
if (area != null) {
    area.setRangeY(w.getMaxHeight(), w.getMinHeight()); // was missing — defaulted to y=64
    area.setLineStyle(2, 0.8, 0x3388FF);
    area.setFillStyle(0.15, 0x3388FF);
}

• DynmapHookTest — adds world min/max height stubs (-64/320) and three new tests verifying setRangeY is called correctly for internal island markers, polygon markers, and area markers

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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