Custom chat render for agent skills

[pwang347]

Depends on microsoft/vscode#286839
Handles the invocation text changes

Fixes microsoft/vscode#286213

[Copilot]

Pull request overview

This PR adds custom chat rendering for agent skills, modifying how skill file operations are displayed in the chat UI. The changes distinguish skill files from regular files in invocation messages, providing clearer context when agent tools interact with skill files.

Key changes:

• Extended ICustomInstructionsService interface with isSkillMdFile and getSkillInfo methods
• Modified ReadFileTool.prepareInvocation to render skill-specific invocation messages
• Added formatUriForFileWidget support for custom file name metadata via optional parameters

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/platform/customInstructions/common/customInstructionsService.ts	Added new interface methods and refactored skills location matching to return skill metadata; includes helper methods for skill directory/name extraction
src/platform/test/common/testCustomInstructionsService.ts	New mock service implementation for testing custom instructions functionality
src/extension/tools/common/toolUtils.ts	Extended formatUriForFileWidget to support optional file name metadata
src/extension/tools/node/readFileTool.tsx	Modified prepareInvocation to display skill-specific messages when reading skill files
src/extension/tools/node/getErrorsTool.tsx	Updated formatURIs call to be explicit about parameter passing
src/extension/tools/node/findTestsFilesTool.tsx	Updated formatURIs call to be explicit about parameter passing
src/extension/tools/node/test/readFile.spec.tsx	Added comprehensive tests for skill file rendering in prepareInvocation
src/extension/tools/node/test/editFileToolUtils.spec.ts	Refactored to use shared MockCustomInstructionsService instead of inline mock