refactor: remove forwardRef in favor of ref as a prop (React 19)

[joshunrau]

Summary

Removes every use of React.forwardRef from the library. Since we now support React 19 only, ref is passed as an ordinary prop to function components.

• 47 components across ArrowToggle, Button, Card, Checkbox, DatePicker, DropdownButton, DropdownMenu, HoverCard, Input, Label, Popover, Select, Separator, Sheet, Slider, Table, Tabs, TextArea and Tooltip are now plain function components.
• Wrappers around Radix primitives are typed with React.ComponentProps<typeof Primitive> instead of ComponentPropsWithoutRef + ElementRef. Wrappers around HTML elements use React.ComponentProps<'tag'>.
• Exported props types now include ref, so consumers can keep passing refs: ButtonProps, ArrowToggleProps, InputProps, TextAreaProps, CalendarProps, DatePickerProps, PopoverContentProps, TooltipContentProps, TooltipTriggerProps, SheetContentProps, DropdownMenuContentProps.
• JSX, class names, defaults and the order of ref and {...props} are unchanged.

Test plan

• tsc --noEmit passes
• eslint src passes
• vitest run: 39 files, 201 tests passing

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🎉 This PR is included in version 6.18.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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