Modal submit data: expose select components (role/channel) and values

[ADG08]

Summary

InteractionModalSubmit does not currently expose modal select submit data (role/channel selects) in a usable typed way.

Discord modal submit payloads can include wrapped components (type: 18) containing select components (type: 6 role, type: 8 channel) with selected values and resolved objects.

Current state in discordgo

ModalSubmitInteractionData currently exposes:

• CustomID
• Components []MessageComponent

This works for text inputs, but modal select submissions do not provide an equivalent typed access path to selected values/resolved entities like other interaction data.

Proposed change (low-level mapping only)

Extend modal submit data mapping so users can read, from modal submit payloads:

• inner component custom_id
• selected values
• optional resolved data (roles/channels/users/members)

Keep backward compatibility for text-input modals and avoid adding high-level helpers.

Notes

If this direction is OK, I can open a PR against master with tests for:

• role select inside modal submit
• channel select inside modal submit
• existing text input modal submit behavior unchanged