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/.storybook/main.ts

@@ -15,7 +15,11 @@
 import type { StorybookConfig } from "@storybook/react-vite";
 
 const config: StorybookConfig = {
-  stories: ["../src/**/*.stories.@(js|jsx|mjs|ts|tsx)"],
+  // v2 components have their own theme-isolated Storybook (.storybook-v2).
+  stories: [
+    "../src/**/*.stories.@(js|jsx|mjs|ts|tsx)",
+    "!../src/v2/**",
+  ],
   addons: [
     import.meta.resolve("@chromatic-com/storybook"),
     import.meta.resolve("@storybook/addon-vitest"),