TS GO API: add getCompletionsAtPosition to the API and support includeSymbols

[piotrtomiak]

This adds one of missing APIs for WebStorm support. It adds support for including symbols in the returned completion items list. This required adding an internal data type CompletionList and CompletionItem, which can store a symbol. Most of the changes in completions.go are about switching from lspproto to internal data type.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a new API surface to fetch language-service completions at an arbitrary document position, optionally including symbol handles for returned entries.

Changes:

• Introduces getCompletionsAtPosition request/response types and Session routing/handler.
• Refactors internal completion plumbing to return an internal CompletionList/CompletionItem wrapper that can carry optional *ast.Symbol.
• Adds native-preview (sync + async) client methods, enums/types, and tests for the new completions API.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
internal/ls/string_completions.go	Switches string/path completion conversion to internal CompletionList/CompletionItem wrappers.
internal/ls/completions.go	Adds internal completion types, symbol-carrying items, includeSymbols plumbing, and LSP conversion helpers.
internal/api/session.go	Wires new method and implements handler to return completion entries + optional symbol handles.
internal/api/proto.go	Adds MethodGetCompletionsAtPosition and request/response DTOs.
_packages/native-preview/test/sync/api.test.ts	Adds sync client tests for checker.getCompletionsAtPosition.
_packages/native-preview/test/async/api.test.ts	Adds async client tests for checker.getCompletionsAtPosition.
_packages/native-preview/src/enums/completionItemKind.ts	Adds runtime CompletionItemKind export for native-preview.
_packages/native-preview/src/enums/completionItemKind.enum.ts	Adds typed enum definition for CompletionItemKind.
_packages/native-preview/src/api/sync/types.ts	Adds completion-related public types and kind typing.
_packages/native-preview/src/api/sync/api.ts	Adds sync Checker.getCompletionsAtPosition and exports CompletionItemKind.
_packages/native-preview/src/api/proto.ts	Adds completion DTOs for client/server wire format.
_packages/native-preview/src/api/async/types.ts	Adds completion-related public types and kind typing.
_packages/native-preview/src/api/async/api.ts	Adds async Checker.getCompletionsAtPosition and exports CompletionItemKind.