WIP: feat(scene) initial beauty baseline — terrain textures, sky, foam, mist, foliage, shadows

- Add 3 Terrain3D texture assets (limestone, valley grass, warm soil)
- Sculpt initial Terrain3D heightmap with ridge, valley, waterfall drop
- Replace plain water with emissive-tinged material
- Add foam mesh, mist spheres, and procedural sky with valley fog
- Add 10 StylizedTree instances around village perimeter
- Enable directional light shadows with extended cascade range
- Add tree height snapping to terrain surface
- Add refined scaffold tests for material count, terrain height, foliage, sky, fog
- Add terrain texture PNGs and StylizedTree.tscn scene
- Add generate_jajce_terrain.gd tool

terrain/jajce/textures/soil_albedo.png.import

@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://b75t0ego2sdja"
+path="res://.godot/imported/soil_albedo.png-ea48d391fd40c4b02fb09bdb7bd9897d.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://terrain/jajce/textures/soil_albedo.png"
+dest_files=["res://.godot/imported/soil_albedo.png-ea48d391fd40c4b02fb09bdb7bd9897d.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=true
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1