feat: get prompt model names (#13607)

fix AI-419

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- New Features
- New API to fetch available models for a prompt, returning default,
optional, and pro models with human‑readable names.
- Added temperature and topP settings to prompt configuration for finer
control.
- Refactor
- When no model is chosen, the default model is used instead of
auto-picking a pro model.
- Model metadata across providers now includes readable names, improving
listings and selection UX.
- Tests
- Updated test snapshots and descriptions to reflect the new
default-model behavior.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/schema.gql

@@ -226,6 +226,9 @@ type Copilot {
   contexts(contextId: String, sessionId: String): [CopilotContext!]!
   histories(docId: String, options: QueryChatHistoriesInput): [CopilotHistories!]! @deprecated(reason: "use `chats` instead")
 
+  """List available models for a prompt, with human-readable names"""
+  models(promptName: String!): CopilotModelsType!
+
   """Get the quota of the user in the workspace"""
   quota: CopilotQuota!
 
@@ -360,6 +363,17 @@ type CopilotMessageNotFoundDataType {
   messageId: String!
 }
 
+type CopilotModelType {
+  id: String!
+  name: String!
+}
+
+type CopilotModelsType {
+  defaultModel: String!
+  optionalModels: [CopilotModelType!]!
+  proModels: [CopilotModelType!]!
+}
+
 input CopilotPromptConfigInput {
   frequencyPenalty: Float
   presencePenalty: Float