Initial commit: FA 2.0 Design System foundation

Token pipeline (Style Dictionary v4, DTCG format):
- Primitive tokens: colour palettes (brand, sage, neutral, feedback),
  typography (3 font families, 21-variant type scale), spacing (4px grid),
  border radius, shadows, opacity
- Semantic tokens: text, surface, border, interactive, feedback colours;
  typography roles; layout spacing
- Component tokens: Button (4 sizes), Input (2 sizes)
- Generated outputs: CSS custom properties, JS ES6 module, flat JSON

Atoms (3 components):
- Button: contained/soft/outlined/text × primary/secondary, 4 sizes,
  loading state, underline for text variant
- Typography: 21 variants across display/heading/body/label/caption/overline,
  maxLines truncation
- Input: external label, helper text, error/success validation,
  start/end icons, required indicator, 2 sizes, multiline support

Infrastructure:
- MUI v5 theme with full token mapping
- Storybook 8 with autodocs
- Claude Code agents and skills for token/component workflows
- Design system documentation and cross-session memory

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tokens/semantic/spacing.json

@@ -0,0 +1,22 @@
+{
+  "spacing": {
+    "component": {
+      "$type": "dimension",
+      "$description": "Component-level spacing — internal padding and gaps within components.",
+      "xs": { "$value": "{spacing.1}",  "$description": "4px — tight gaps: icon margins, chip internal padding" },
+      "sm": { "$value": "{spacing.2}",  "$description": "8px — small padding: badge padding, inline element gaps" },
+      "md": { "$value": "{spacing.4}",  "$description": "16px — default padding: button padding, input padding, form field gap" },
+      "lg": { "$value": "{spacing.6}",  "$description": "24px — large padding: card padding (desktop), modal padding" }
+    },
+    "layout": {
+      "$type": "dimension",
+      "$description": "Layout-level spacing — structural gaps between sections and page elements.",
+      "gutter":              { "$value": "{spacing.4}",  "$description": "16px — grid gutter on mobile, card grid gap" },
+      "gutter-desktop":      { "$value": "{spacing.6}",  "$description": "24px — grid gutter on desktop" },
+      "section":             { "$value": "{spacing.12}", "$description": "48px — vertical gap between page sections" },
+      "page":                { "$value": "{spacing.16}", "$description": "64px — major page section separation, hero spacing" },
+      "page-padding":        { "$value": "{spacing.4}",  "$description": "16px — horizontal page padding on mobile" },
+      "page-padding-desktop": { "$value": "{spacing.8}", "$description": "32px — horizontal page padding on desktop" }
+    }
+  }
+}