Generate real glossy reel-symbol art and close the visual gap further

Hand-authored 6 gradient-shaded SVG icons (gold coin, purple gem,
green potion, blue RZ shield, coin stack, gift box) to replace the
flat monochrome placeholder icons in the reels and reward list - no
image-generation tool is available here, so this is genuine vector
art with radial/linear gradients and highlight layers rather than a
literal asset match to the mockup's renders.

Combined with real Godot techniques: a layered-label glow effect on
the "RZ" marquee, chase-lit marquee bulbs down both sides of the
reel screen (looping Tweens), a much more pronounced arch silhouette
and neon border on the cabinet, and an overall scale-up (bigger
reels, marquee, lever) so the machine reads as the dominant element
instead of a cramped placeholder. Verified with an actual rendered
screenshot (not just structural checks) at each iteration.

assets/icons/slots/slot_coin.svg.import

@@ -0,0 +1,43 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://baothvvse1io2"
+path="res://.godot/imported/slot_coin.svg-d58109e8f39477605be91302ac3d3e1b.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://assets/icons/slots/slot_coin.svg"
+dest_files=["res://.godot/imported/slot_coin.svg-d58109e8f39477605be91302ac3d3e1b.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
+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
+svg/scale=1.0
+editor/scale_with_editor_scale=false
+editor/convert_colors_with_editor_theme=false