Long context pricing

[lramos15]

Fix #317575

[Copilot]

Pull request overview

Adds support for “long context” (tiered) pricing metadata for language models and surfaces it in relevant VS Code Chat UI hovers, aligned with the updated Copilot API pricing structure.

Changes:

• Extend language model pricing metadata (proposed API + internal metadata + ext host marshalling) with optional long-context cost fields.
• Show long-context cost details in the model picker hover and the chat models management hover content.
• Update Copilot extension token pricing normalization to a tiered { default, longContext? } structure and bump @vscode/copilot-api to ^0.4.0.

Show a summary per file

File	Description
src/vscode-dts/vscode.proposed.languageModelPricing.d.ts	Adds optional longContext*Cost fields to the proposed API types.
src/vs/workbench/contrib/chat/common/languageModels.ts	Extends internal ILanguageModelChatMetadata with long-context pricing fields.
src/vs/workbench/contrib/chat/browser/widget/input/chatModelPicker.ts	Renders a second “Long context cost” section in the model picker hover when present.
src/vs/workbench/contrib/chat/browser/chatManagement/chatModelsWidget.ts	Adds long-context pricing section to the markdown hover content.
src/vs/workbench/api/common/extHostLanguageModels.ts	Marshals long-context pricing fields from extensions into workbench metadata (and back into API objects).
package.json	Bumps @vscode/copilot-api to ^0.4.0.
package-lock.json	Updates lock entry for @vscode/copilot-api@0.4.0.
remote/package.json	Bumps @vscode/copilot-api to ^0.4.0 for remote.
remote/package-lock.json	Updates remote lock entry for @vscode/copilot-api@0.4.0.
extensions/copilot/src/platform/networking/common/networking.ts	Introduces tier types (ITokenPriceTier, tiered IChatEndpointTokenPricing).
extensions/copilot/src/platform/endpoint/node/chatEndpoint.ts	Normalizes tiered pricing (default + optional long_context) into per-1M token rates.
extensions/copilot/src/platform/endpoint/common/endpointProvider.ts	Updates raw billing token price type shape to tiered structure.
extensions/copilot/src/extension/conversation/common/languageModelAccess.ts	Uses pricing.default.* for labels after pricing shape change.
extensions/copilot/src/extension/conversation/vscode-node/languageModelAccess.ts	Emits both default and long-context costs into model metadata.
extensions/copilot/src/extension/chatSessions/claude/node/claudeCodeModels.ts	Emits both default and long-context costs for Claude code models.
extensions/copilot/package.json	Bumps @vscode/copilot-api to ^0.4.0 in Copilot extension.
extensions/copilot/package-lock.json	Updates Copilot extension lock entry for @vscode/copilot-api@0.4.0.
extensions/copilot/chat-lib/package.json	Bumps @vscode/copilot-api to ^0.4.0 in chat-lib package.

Copilot's findings

Files not reviewed (2)

• extensions/copilot/package-lock.json: Language not supported
• remote/package-lock.json: Language not supported

• Files reviewed: 14/18 changed files
• Comments generated: 2