## What kind of change does this PR introduce?
Bug fix / design-system alignment for the legacy `Button` from `ui`.
## What is the current behavior?
Omitting `variant` on the legacy `Button` falls back to brand-green
`primary`. That makes accidental greens easy, and it is hard to spot the
real main action on busy pages.
## What is the new behavior?
- Legacy `Button` now defaults to neutral `default`
- Intentional primary CTAs (create, save, submit, marketing CTAs, and
matching `ButtonTooltip` usages) now set `variant="primary"` so their
appearance is unchanged
- Neutral actions that previously relied on the old fallback (cancel,
close, back, dashboard nav, and similar) become grey/white
- Design-system docs updated; regression tests cover the new default
`Button_Shadcn_` is unchanged. It already uses its own CVA default.
This is PR 1 of 2 in a stack. PR 2 drops now-redundant
`variant="default"` props.
## To test
Studio (http://localhost:8082):
- `/sign-in`: Sign in stays green
- Open a project → Database → Tables: New table stays green
- Auth → Users → Invite: Invite user stays green; Cancel / dismiss
controls stay neutral
- Project Settings → General: edit a field so Cancel and Save appear.
Cancel is neutral, Save is green
Design system (http://localhost:3003):
- Components → Button: default demo is neutral; primary demo is green;
featured preview is the default variant
Marketing (optional):
- www header: Start your project stays green; logged-in Dashboard is
neutral
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
- **Style**
- Buttons now default to a neutral style, while primary actions across
Studio, documentation, marketing pages, forms, dialogs, and error states
use prominent primary styling.
- Updated button examples and previews clarify the distinction between
default and primary variants.
- Event registration now includes a directional arrow icon.
- **Tests**
- Added coverage confirming default button styling and explicit primary
styling behave as expected.
- Updated related test fixtures to use primary styling where
appropriate.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Danny White