This PR fixes three issues:
1. Token bound_channel_id not updating: Add bound field to Update() method
2. Channel pricing quota_type detection: Use QuotaTypeByCall constant instead of magic number 1
3. Log display for ratio-based pricing: Set ModelPrice=-1 for ratio-based pricing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Add a new /api/user/channels endpoint that returns only enabled channels
with non-sensitive fields (id, name, type, remark) for token channel binding.
Update EditTokenModal to use this endpoint and display remark instead of ID
in the channel dropdown.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

- GetAllChannelPricing: get all channel pricings with pagination
- GetChannelPricingByModel: get pricings for a specific model
- CreateChannelPricing: create or update channel pricing
- BatchCreateChannelPricing: batch create/update pricings
- DeleteChannelPricing: delete channel pricing
- CopyGlobalPricing: copy global pricing from ratio_setting to channel
- GetChannelPricingWithTags: get pricings with tag details

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>