initial commit: gd-controls plugin scaffolding

- promptfont font assets and license
- key_mapping CSVs for Godot input bindings and prompt-font glyphs
  across keyboard/mouse, PC/Xbox/Sony/Nintendo controllers, and touch
- gen.py generates prompt_font_mapping.gd from key_mapping/promptfont.csv,
  splicing between STARTGEN/ENDGEN markers
- device, manager, file_manager scaffolding (work in progress)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fonts/promptfont/preview.png.import

@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://dketekofafye3"
+path="res://.godot/imported/preview.png-77f4630472c09587c75dd6977ce13622.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://addons/gd-controls/fonts/promptfont/preview.png"
+dest_files=["res://.godot/imported/preview.png-77f4630472c09587c75dd6977ce13622.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