feat: support launching agents/vscode app without protocol handler

[deepak1556]

Fixes https://github.com/microsoft/vscode-internalbacklog/issues/6966

[github-actions]

Screenshot Changes

Base: 3267a57d Current: 360d5a75

Changed (2)

chat/aiCustomizations/aiCustomizationManagementEditor/McpBrowseMode/Light

Before	After

editor/inlineChatAffordance/InlineChatOverlay/Light

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[Copilot]

Pull request overview

This PR adds a native “launch sibling app” pathway (host ↔ embedded) so Agents/VS Code can be launched without relying on OS protocol handler registration, improving robustness for packaged/enterprise scenarios.

Changes:

• Add INativeHostService.launchSiblingApp() and implement it in the Electron main process using a new platform/native/node/siblingApp.ts helper.
• Switch “Open Agents Application” to launch the sibling app directly on macOS/Windows (built builds).
• Add a Sessions desktop contribution to “Open in VS Code” by launching the host app with CLI args, and extend product/build metadata to support sibling bundle IDs.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/vs/workbench/test/electron-browser/workbenchTestServices.ts	Adds a test stub for the new native host API.
src/vs/workbench/contrib/chat/electron-browser/agentSessions/agentSessionsActions.ts	Uses native sibling-app launch instead of protocol opener in built desktop scenarios.
src/vs/sessions/sessions.desktop.main.ts	Registers a desktop-specific “Open in VS Code” override contribution.
src/vs/sessions/contrib/chat/electron-browser/openInVSCode.contribution.ts	Implements desktop override that launches the host app with --folder-uri and --open-url.
src/vs/platform/native/node/siblingApp.ts	New helper to resolve & spawn the sibling application per-platform.
src/vs/platform/native/electron-main/nativeHostMainService.ts	Wires the new method through the main-process native host service.
src/vs/platform/native/common/native.ts	Extends native host interface with launchSiblingApp.
src/vs/code/node/cli.ts	Reuses sibling resolution logic for --agents on Windows; simplifies macOS embedded launch to open -b.
src/vs/base/common/product.ts	Adds darwinSiblingBundleIdentifier to product configuration types.
build/lib/embeddedType.ts	Extends embedded product info typing with optional sibling bundle identifier.
build/gulpfile.vscode.ts	Preserves host darwinSiblingBundleIdentifier when generating product.sub.json for embedded builds.