Add local-vscode-extension-rig and migrate VS Code extensions to it

[iclanton]

Summary

Adds a new local local-vscode-extension-rig and migrates the repo's VS Code extension projects from the public @rushstack/heft-vscode-extension-rig to it. The new rig delegates to local-node-rig and no longer enables skipLibCheck, which surfaced several pre-existing declaration-file type errors (previously suppressed) plus one genuine source bug. This PR fixes all of them so the affected projects build cleanly.

Why the build broke

The old public rig set "skipLibCheck": true, which silently hid type errors inside .d.ts files. The new rig does not, so tsc now checks declaration files and reports issues that were always present.

Changes

New rig

• rigs/local-vscode-extension-rig — profiles, eslint includes, heft/typescript/jest/rush-project config, webpack base.

Migrated projects (rig.json, heft.json, rush-project.json, eslint.config.js, webpack.config.js, package.json, tsconfig.json):

• vscode-extensions/rush-vscode-extension
• vscode-extensions/debug-certificate-manager-vscode-extension
• vscode-extensions/playwright-local-browser-server-vscode-extension

Type fixes

• rush-vscode-extension (TS2403 ×7): the rig forces "types": ["jest", "node"], whose ambient test globals (describe/it/beforeEach) collide with this project's @types/mocha (it uses Mocha + @vscode/test-electron for VS Code integration tests). Overrode types to ["mocha", "node"] in the project's tsconfig.json.
• rush-vscode-command-webview (TS2315): IFromExtensionMessage lived in fromExtension.ts alongside fromExtensionListener, which uses the DOM-generic MessageEvent<T>. When the Node-based extension imported the type via the package barrel, MessageEvent resolved to the non-generic @types/node declaration. Extracted the contract into a new DOM-free module src/Message/IFromExtensionMessage.ts and re-pointed the barrel at it.
• playwright-local-browser-server (TS2304): playwright-core's type definitions reference DOM types (Node, HTMLElement, SVGElement). Added "lib": ["DOM"] to the project's tsconfig.json, matching the existing convention in apps/playwright-browser-tunnel.
• rush-vscode-extension/src/test/suite/index.ts (TS2794): real source bug — new Promise(...) inferred Promise<unknown> so resolve() required an argument.

Also includes eslint --fix import-order and node: protocol cleanups picked up by the pre-commit hook.

Notes

• No rush change files were added: all affected projects are non-published (private rigs/webview, or vsix-tagged apps / shouldPublish: false). rush change --verify passes.
• This is the minimal "get green" change. A follow-up could modernize the VS Code test tooling (@vscode/test-electron 1.x → 3.x, adopt @vscode/test-cli) and split unit (Jest) vs. integration (Mocha-in-host) tests, but that is intentionally out of scope here.

Testing

• rush build across all migrated projects + dependents: green (lint warnings only, all pre-existing/unrelated).
• rush test --only . on the affected projects: passes.
• rush change --verify: passes.