(jsx/tsx) Improve slot type safety with dedicated slots prop

[ElYaiko]

Current issue:
The JSX/TSX slot syntax offers no type checking or autocomplete:

<Component>{{ default: () => ..., otherSlot: ({ item }) => item.name }}</Component>

Proposal:
Support a typed slots prop for better DX:

<Component slots={{
  default: () => ...,
  otherSlot: ({ item }) => item.name // Item is typed
}} />

Benefits:

• Full TypeScript inference for slot names and props
• IDE autocomplete
• Clear error messages
• Aligns with JSX ecosystem patterns

This would dramatically improve TSX developer experience for component libraries.

[ShGKme]

• Probably a duplication of Strict type Children in Slots #733

[ElYaiko]

• Probably a duplication of Strict type Children in Slots #733

Seems not, this is for JSX/TSX #733 is for SFC.