phsl / new-api

Previously, the Playground UI allowed users to pick a group, but the request body sent to `/pg/chat/completions` did not include this information, so the backend always fell back to the user’s default group.

Changes introduced
• web/src/helpers/api.js – added `group: inputs.group` to the `payload` built in `buildApiPayload`.

Outcome
• Selected group is now transmitted to the backend, enabling proper channel routing and pricing logic based on group ratios.
• Resolves the issue where group selection appeared ineffective in the Playground.