Upgrade TypeScript to 7.0.1 RC

[ConnorQi01]

Summary

Upgrade the main TypeScript dependency to 7.0.1 RC and update the local build pipeline so the repository can compile with the TS7 CLI package.

Proposed Changes

• Upgrade typescript to 7.0.1-rc.
• Remove @typescript/native-preview, gulp-typescript, and ts-loader from the main project dependencies.
• Add a small TypeScript CLI wrapper and route gulp/webpack TypeScript compilation through it because TS7 RC does not expose the legacy JavaScript compiler API used by the old build path.
• Skip ESLint when the installed TypeScript package does not expose the legacy JavaScript API.
• Update compatibility issues found during the TS7 migration, including CommonJS default interop and affected import styles.
• Increase the timeout for an existing async packager test that was repeatedly timing out under the VS Code extension host during pre-push validation.

Test Plan

• npm run build
• npx tsc --noEmit -p tsconfig.json --pretty false
• npm test
• Pre-push hook build and tests passed during git push

Closes #2764