feat(Inline): add justifyContent prop support

[Marcosld]

Summary

The Inline component currently does not expose a justifyContent prop for endpoint-alignment values, which limits horizontal alignment control when the component's items do not fill the full container width.

Motivation

The space prop already accepts 'between' | 'around' | 'evenly', covering the distributional justify-content values. What is not currently possible is pushing a group of items to the right or centre of the container — for example, placing a single action button flush-right in a card header:

// Not achievable today — no way to right-align the group
<Inline space={16} justifyContent="flex-end">
  <Button variant="secondary">Cancel</Button>
  <Button variant="primary">Save</Button>
</Inline>

This forces consumers to wrap Inline in an extra element with custom CSS, adding unnecessary complexity.

Proposed API

Add a justifyContent prop restricted to the values not already covered by space:

<Inline space={16} justifyContent="flex-end">
  <Tag type="active">Active</Tag>
  <Tag type="inactive">Inactive</Tag>
</Inline>

Suggested accepted values:

Value	Description
"flex-start" (default)	Items aligned to the start — current behaviour
"flex-end"	Items aligned to the end (right in LTR)
"center"	Items centred horizontally

space-between, space-around, and space-evenly are already handled by the space prop and do not need to be duplicated here.

Acceptance criteria

• Inline accepts an optional justifyContent prop ("flex-start" | "flex-end" | "center").
• The default value preserves current behaviour ("flex-start").
• The prop is reflected in the rendered container's justify-content CSS property.
• TypeScript types are updated.
• Storybook story demonstrates at least two values ("flex-start" and "flex-end").
• Existing snapshot/unit tests remain green.

Additional context

This request was raised while building a metrics dashboard that uses Inline to place action buttons flush-right in a card header. Without justifyContent: "flex-end", the layout requires an extra wrapper element.

[yceballost]

Should we include the same values that we support in Grid?