Add settings screen and adult space with progress report and save export/restore (0.4.0)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

assets/interface/slider_grabber.svg.import

@@ -0,0 +1,43 @@
+[remap]
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+uid="uid://mqgtoutc6apf"
+path="res://.godot/imported/slider_grabber.svg-b318c142ebe6680738fc52de4bcd86af.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://assets/interface/slider_grabber.svg"
+dest_files=["res://.godot/imported/slider_grabber.svg-b318c142ebe6680738fc52de4bcd86af.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=false
+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
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+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
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+detect_3d/compress_to=1
+svg/scale=1.0
+editor/scale_with_editor_scale=false
+editor/convert_colors_with_editor_theme=false