Component: Button migration 1: TextButton (#7537)

## Summary

Setup the variants and migrate existing uses of
TextButton/TextIconButton/IconButton to a single Button component.

Still a work in progress.

## Changes

- **What**: Add a new Button
- **What**: Migrate old buttons
- **What**: Delete old buttons
- **Dependencies**: CVA, upgrade Storybook

## Review Focus

<!-- Critical design decisions or edge cases that need attention -->

<!-- If this PR fixes an issue, uncomment and update the line below -->
<!-- Fixes #ISSUE_NUMBER -->

## Screenshots (if applicable)

<!-- Add screenshots or video recording to help explain your changes -->

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7537-WIP-Component-Button-migration-2cb6d73d36508156a81bfc7bbddb36e9)
by [Unito](https://www.unito.io)

---------

Co-authored-by: GitHub Action <action@github.com>

src/components/ui/button/button.variants.ts

@@ -0,0 +1,49 @@
+import type { VariantProps } from 'cva'
+import { cva } from 'cva'
+
+export const buttonVariants = cva({
+  base: 'inline-flex items-center justify-center gap-2 cursor-pointer whitespace-nowrap appearance-none border-none rounded-md text-sm font-medium font-inter transition-colors focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:pointer-events-none disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0',
+  variants: {
+    variant: {
+      secondary:
+        'bg-secondary-background text-secondary-foreground hover:bg-secondary-background-hover',
+      primary:
+        'bg-primary-background text-base-foreground hover:bg-primary-background-hover',
+      inverted:
+        'bg-base-foreground text-base-background hover:bg-base-foreground/80',
+      destructive:
+        'bg-destructive-background text-base-foreground hover:bg-destructive-background-hover',
+      textonly:
+        'text-base-foreground bg-transparent hover:bg-secondary-background-hover',
+      'muted-textonly':
+        'text-muted-foreground bg-transparent hover:bg-secondary-background-hover'
+    },
+    size: {
+      sm: 'h-6 rounded-sm px-2 py-1 text-xs',
+      md: 'h-8 rounded-lg p-2 text-xs',
+      lg: 'h-10 rounded-lg px-4 py-2 text-sm',
+      icon: 'size-9'
+    }
+  },
+
+  defaultVariants: {
+    variant: 'secondary',
+    size: 'md'
+  }
+})
+
+export type ButtonVariants = VariantProps<typeof buttonVariants>
+
+const variants = [
+  'secondary',
+  'primary',
+  'inverted',
+  'destructive',
+  'textonly',
+  'muted-textonly'
+] as const satisfies Array<ButtonVariants['variant']>
+const sizes = ['sm', 'md', 'lg', 'icon'] as const satisfies Array<
+  ButtonVariants['size']
+>
+
+export const FOR_STORIES = { variants, sizes } as const