feat(vscode): add test recognition to vscode

[benfdking]

[benfdking]

Small tweaks to improve

[Copilot]

Pull Request Overview

This PR adds test recognition and execution capabilities to the VS Code extension, enabling users to discover, view, and run SQLMesh tests directly within the editor's test runner interface.

• Implements LSP methods for listing workspace tests, document-specific tests, and running individual tests
• Adds VS Code test controller integration to display tests in the Test Explorer panel
• Creates test range detection functionality to provide accurate line number mappings for test entries

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
vscode/extension/tests/tests.spec.ts	End-to-end test for the new test functionality
vscode/extension/src/tests/tests.ts	Main test controller implementation for VS Code
vscode/extension/src/lsp/lsp.ts	Type casting fix for error handling
vscode/extension/src/lsp/custom.ts	TypeScript interface definitions for new LSP methods
vscode/extension/src/extension.ts	Integration of test controller into the extension
tests/lsp/test_context.py	Unit tests for LSP context test methods
sqlmesh/lsp/tests_ranges.py	YAML parsing utility for extracting test ranges
sqlmesh/lsp/main.py	LSP server handlers for test-related methods
sqlmesh/lsp/custom.py	Python class definitions for LSP test methods
sqlmesh/lsp/context.py	Core test discovery and execution logic