New extension layout

[jakebailey]

Fixes #3722
For #3727

This restructures our extensions into:

• A new extension vscode-typescript, displayed as TypeScript 7. This is the client extension that goes into VS Code. It carries bundled TS/tsgo bits for now, and requires VS Code 1.126+ so the built-in extension recognizes both the new and old extension IDs.
• The old extension native-preview becomes the TypeScript 7 Nightly extension. It is now just the nightly version box; if installed, vscode-typescript prefers its contents over the bundled contents, matching how the built-in TypeScript extension uses TypeScript Nightly.
• If native-preview is installed by itself, it installs vscode-typescript so existing users still end up with the real client extension.
• vscode-typescript self-manages the existing useTsgo handoff so current VS Code can switch between Strada and Corsa. It supports the normal version selector flow, but uses private command IDs for the Corsa handlers so the two extensions do not register the same command IDs.
• vscode-typescript now respects js/ts.* settings instead of typescript.native-preview.*, with back compat and deprecation messages for now.
• Packaging now emits both VSIX families from this repo, and the visible extension/output names have been updated for TypeScript 7.

[Copilot]

Pull request overview

This PR restructures the VS Code extension layout by splitting the current extension into a new “main” extension (vscode-typescript) and a separate nightly extension (native-preview), while migrating configuration to js/ts.* settings (with legacy typescript.native-preview.* still supported via deprecation/back-compat).

Changes:

• Add a new _extension-nightly workspace/package and update workspace wiring (package.json, package-lock.json).
• Update build/packaging to produce VSIX artifacts for both the main and nightly extensions (Herebyfile.mjs).
• Migrate configuration and UX strings to the new js/ts.* settings and “TypeScript 7 Native Preview” naming across extension + LSP preference handling.

Reviewed changes

Copilot reviewed 21 out of 22 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
package.json	Adds _extension-nightly to the monorepo workspaces.
package-lock.json	Updates workspace package names/links for vscode-typescript and native-preview (nightly).
internal/project/customconfigfilename_test.go	Updates preference parsing test to use js/ts.customConfigFileName directly.
internal/ls/lsutil/userpreferences.go	Changes CustomConfigFileName config mapping to match the new js/ts layout.
Herebyfile.mjs	Extends VSIX packaging to build both “typescript-vscode” and “typescript-nightly” artifacts.
_extension/src/util.ts	Adds new TSDK candidate resolution and optional nightly exe selection plumbing; adds shared naming constants.
_extension/src/statusBar.ts	Updates UI strings to “TypeScript 7 Native Preview”.
_extension/src/session.ts	Migrates config reads/updates to js/ts.* and adjusts UI text accordingly.
_extension/src/projectStatus.ts	Updates project status UI name.
_extension/src/extension.ts	Reacts to new TSDK-related settings and updates onboarding/enablement behavior.
_extension/src/configurationMiddleware.ts	Merges js/ts + legacy typescript.native-preview settings for server config back-compat.
_extension/src/commands.ts	Updates documentation comment to the new extension name.
_extension/src/client.ts	Updates LanguageClient naming/branding and config reads.
_extension/README.md	Updates README for new extension name and js/ts.tsdk.path configuration.
_extension/package.nls.json	Updates extension description and adds deprecation messages for legacy settings keys.
_extension/package.json	Renames the extension package to vscode-typescript, contributes js/ts.* settings, and deprecates old ones.
_extension/l10n/bundle.l10n.json	Updates localization keys/strings for new naming and one new error string.
_extension-nightly/src/extension.js	Adds a small “nightly” extension that auto-installs the replacement extension when missing.
_extension-nightly/README.md	Documents the nightly extension’s purpose and relationship to the main extension.
_extension-nightly/package.nls.json	Adds marketplace description string.
_extension-nightly/package.json	Defines the nightly extension package metadata and activation.
_extension-nightly/LICENSE	Adds Apache 2.0 license text for the new nightly extension package.

[Copilot]

Pull request overview

Copilot reviewed 22 out of 23 changed files in this pull request and generated 2 comments.

[DanielRosenwasser]

For some reason, I am not able to get expandable hovers when using a local VS Code version. This was probably due to a weird mix of package-lock.json + pnpm