Channel model_mapping keys exposed in a channel's model list now act as
first-class aliases for task-plugin models across the whole line:
- Derived alias view (model/task_model_alias.go): built from enabled
channels' model_mapping, chain-following with cycle detection, declared
names always win, cross-plugin conflicts dropped. Rebuilt on channel
cache refresh, registry generation change, and a 60s TTL.
- Request path: PinTaskPluginEndpoint resolves declared-name case folds
and mapping aliases before endpoint lookup (never rewriting the body
until the endpoint is claimed), pins with MappedModel, and the decode
contract accepts alias echoes without loosening model ownership for
normal pins. Legacy /v1/tasks submit folds case variants the same way.
Fixes aliases on POST /v1/responses silently falling through to the
main relay against task channels.
- Mapping order: ModelMappedHelper now runs before the plugin submit
hook builds and caches the upstream body, so channel model_mapping
actually reaches the upstream request. Plugins receive the mapped
name as ctx.upstreamModel in both decode and submit contexts.
- Billing: identity stays the origin name; when the alias has no tiered
expression, the selected channel's mapping tail expression applies.
Pricing page and billing-expr smoke tests resolve aliases to the
owning plugin's usage schema.
- Case folding: ASCII-only fold with exact-match priority; same-plugin
and cross-plugin fold collisions rejected at registration.
- Plugins: model-keyed rate tables, req_key derivation, and combo
validation in doubao/kling/jimeng/hailuo/vidu/sunoapi now key on
ctx.upstreamModel || ctx.model; render/echo paths keep ctx.model.
CaIon