Add tabular index (metadata.csv, characters.csv) + card metadata

scripts/README.md

@@ -30,6 +30,7 @@ No token needed.
 | `build_frames.py` | `../animation_frames.json` |
 | `build_characters.py` | `../characters.json` |
 | `check_retarget.py` | `../animation_bones.json`, `../character_bones.json` |
+| `build_tables.py` | `../metadata.csv`, `../characters.csv` (the browsable/loadable index) |
 
 Two small libraries back these, and are useful on their own: