Add v2 Text typography primitive

Implement the first v2 typography component from the Probo Radix UI
Figma: a Text primitive rendering a single span with size, weight,
align, color, and highContrast variants (color x highContrast
resolves to the sand/gold/red/green/amber/sky text step 11 or 12),
plus a paired TextSkeleton. Styling is tailwind-variants only, with
the scale shared through a variants module per the kit guides.

Stand up a theme-isolated v2 Storybook (.storybook-v2) loading the
v2 theme with a light/dark toggle, since v1 and v2 cannot share one
Tailwind build; the v1 build now excludes src/v2.

Signed-off-by: Émile Ré <emile@probo.com>

packages/ui/tsconfig.app.json

@@ -23,5 +23,5 @@
     "noFallthroughCasesInSwitch": true,
     "noUncheckedSideEffectImports": true
   },
-  "include": ["src", ".storybook/**/*"],
+  "include": ["src", ".storybook/**/*", ".storybook-v2/**/*"],
 }