Foundation for collapsing the ~188 add_theme_color_override calls onto Godot
Theme inheritance. Adds a `typeVariations` section to design-tokens.json and
emits each as a Godot type variation in ui_theme.tres.
9 Label variations covering the high-count font_color override patterns:
LabelTitle/Muted/Secondary/Disabled/Positive/Negative/Warning/Gold/Science
(→ text.title/muted/secondary/disabled, semantic.positive/negative/warning,
accent.gold/science). Widgets set `theme_type_variation = "LabelMuted"` to
inherit instead of `add_theme_color_override("font_color", ...)`.
Additive — nothing consumes them yet, zero visual change. Verified: variations
baked into ui_theme.tres, theme --check clean, headless load exit 0.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>