Upgrade to TypeScript 6.0 across monorepo

[nnoce14]

Background:

TypeScript 6.0 has been released with several breaking changes and new capabilities. See below for details: https://devblogs.microsoft.com/typescript/announcing-typescript-6-0/

Tasks:

• Update TypeScript packages in all relevant sub-packages/workspaces to ^6.0.0
• Run a full build and resolve any breaking changes/compile errors
• Review and document any necessary or recommended changes to TypeScript config files in the monorepo for TypeScript 7.0 migration; (@cellix/config-typescript is particularly relevant here)
• Summarize changes, decisions, and any required follow-up tasks in an ADR for TypeScript 6.0 adoption

Acceptance Criteria:

• Monorepo uses the latest TypeScript 6.x version in the pnpm catalog
• No compile errors present after upgrade
• Investigate and recommend any TypeScript config changes that would future-proof the setup for upcoming TypeScript 7.0 native ECMAScript support

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Reference: TypeScript 6.0 announcement