Ensure that the selected "group" filter (and other form search values) persist across
type tab changes, status filter updates, pagination, and page-size changes.
Changes include:
• loadChannels: added `searchParams` argument and now appends keyword, group and model
query strings to API calls.
• refresh / page handlers / type tabs / status Select: now pass current form values
to loadChannels, keeping filters intact.
• searchChannels: maintains active type and status filters when issuing search requests.
• Form.Select (searchGroup): triggers loadChannels when only group filter is active,
preventing parameter loss.
• Minor cleanup and comment adjustments.
