Why: channels with model pricing entries but no model mapping (e.g. azcc with
3 priced claude models, no mapping) were rendering as 未配置模型 in the
'Available Channels' page. The algorithm only iterated ModelMapping and
silently dropped any platform without a mapping entry.
Changes:
- channel.go: SupportedModels now unions mapping + pricing entries.
For exact mapping src → target, pricing is looked up by target (the actually
billed name), not by src.
- channel_available.go: ListAvailable enriches each entry with nil pricing
via PricingService.GetModelPricing (global LiteLLM fallback) so the popover
always shows a price.
- channel_service.go: NewChannelService takes *PricingService as 4th param.
- channel_test.go: rewrote 4 tests that froze the old mapping-only semantics;
added pricing-only / mapping-target / target-missing coverage.
6cd7c60549