Hook up the ability to handle model promos

[Logan Ramos (lramos15)]

No description provided.

[Copilot]

Pull request overview

This PR threads a new optional promo field ({ id, discountPercent, endsAt, message }) through the model-metadata stack so a model can advertise a promotional discount. The data originates from the CAPI billing.promo payload, is normalized in the agent-host pricing layer and the Copilot endpoint, flows through the ext-host bridge into ILanguageModelChatMetadata, and is surfaced in three UI places: the model picker (a boosted entry right after "Auto" plus a discount badge/description), the model hover card (a discount pill + promo message with end date), and a new one-time chat-input notification.

Changes:

• Add promo to the model-metadata/billing interfaces and proposed API .d.ts files, and wire it through every mapping site (CAPI billing → endpoint → ext-host → picker/session providers/agent-host).
• Surface promos in the picker (boost the promo model next to Auto, show a "{n}% discount" description/badge and a promo hover block) and add a new ChatPromoNotificationContribution that shows a dismissible, persisted one-time notification.
• Change ChatEndpoint.degradationReason to drop the info_messages fallback and fold the degradation reason into warningText['degradation'] in languageModelAccess.ts.

Show a summary per file

File	Description
src/vs/platform/agentHost/common/agentModelPricing.ts	Adds promo to pricing meta/billing interfaces plus defensive normalizePromo/read validation and round-trip write.
extensions/copilot/src/platform/endpoint/common/endpointProvider.ts	Adds IModelPromo and billing.promo.
extensions/copilot/src/platform/endpoint/node/chatEndpoint.ts	Maps billing.promo to promo; removes info_messages fallback from degradationReason.
extensions/copilot/src/platform/networking/common/networking.ts	Adds promo to IChatEndpoint.
extensions/copilot/src/extension/conversation/vscode-node/languageModelAccess.ts	Passes promo; folds degradationReason into warningText.
extensions/copilot/src/extension/chatSessions/claude/node/claudeCodeModels.ts	Forwards endpoint.promo.
src/vs/workbench/api/common/extHostLanguageModels.ts	Bridges promo into ILanguageModelChatMetadata.
src/vs/workbench/contrib/chat/common/languageModels.ts	Declares promo on ILanguageModelChatMetadata.
src/vs/workbench/contrib/chat/common/chatSessionsService.ts	Adds promo to option-model metadata.
src/vs/workbench/contrib/chat/browser/chatSessions/chatSessionPickerActionItem.ts	Forwards promo.
src/vs/workbench/contrib/chat/browser/agentSessions/agentHost/agentHostLanguageModelProvider.ts	Forwards promo.
src/vs/sessions/contrib/providers/copilotChatSessions/browser/copilotChatSessionsProvider.ts	Forwards promo.
src/vs/workbench/contrib/chat/browser/widget/input/chatModelPicker.ts	Boosts promo models, adds discount description/badge, and renders promo hover block.
src/vs/workbench/contrib/chat/browser/widget/media/chat.css	Adds .chat-model-hover-promo-text styles (mirrors warning-text).
src/vs/workbench/contrib/chat/browser/chatPromoNotification.ts	New contribution showing a persisted one-time promo notification.
src/vs/workbench/contrib/chat/browser/chat.shared.contribution.ts	Registers the new contribution.
src/vs/vscode-dts/vscode.proposed.chatProvider.d.ts / vscode.proposed.chatSessionsProvider.d.ts	Add promo to proposed API.
src/vs/workbench/contrib/chat/test/browser/widget/input/chatModelPicker.test.ts	Adds picker tests for promo boosting/description/dedup.

Review details

• Files reviewed: 17/19 changed files
• Comments generated: 1
• Review effort level: Medium

[vs-code-engineering]

📬 CODENOTIFY

The following users are being notified based on files changed in this PR:

Tyler James Leonhardt (@TylerLeonhardt)

Matched files:

• extensions/copilot/src/extension/chatSessions/claude/node/claudeCodeModels.ts