phsl / new-api

Summary
1. Load `channel_info` when editing:
   • Detect if the channel is in multi-key mode (`is_multi_key`).
   • Auto-initialize `batch`, `multiToSingle`, and `multiKeyMode` from backend data.

2. Visibility logic
   • Creation page: “Batch create / Multi-key mode” always available.
   • Edit page: show these controls **only when** the channel itself is multi-key.

3. State consistency
   • `multi_key_mode` added to `inputs`; `setValues(inputs)` now preserves the user’s selection.

Result
Single-key channels no longer display irrelevant “key aggregation” options, while multi-key channels open with the correct defaults, providing a cleaner and more accurate editing experience.