chore: use workspaces

[daniel-graham-amplitude]

Summary

This PR updates versions in package.json to use "workspace:*" when it's an internal package. This is so that it uses the internal package instead of fetching it from the NPM repository.

Checklist

• Does your PR title have the correct title format?
• Does your PR have a breaking change?: No

---

Note

Adopts pnpm workspaces and links internal packages via workspace:*, updating tooling and minor code to align with the new setup.

• Switches repo to pnpm: set npmClient to pnpm in lerna.json, add pnpm setup/caching to .github/actions/build-and-test, run pnpm install in .husky/pre-commit, tweak root build script (--skip-nx-cache), and refresh pnpm-lock.yaml
• Replace pinned internal versions with workspace:* across packages (e.g., analytics-*, plugin-*, session-replay-*, gtm-snippet, targeting, unified)
• Add @aws-sdk/client-s3 as a dev dependency in the root and multiple packages used by publish scripts
• Unified SDK: re-export setTransport directly from client and drop explicit type import; minor import tidy in analytics-core debug.ts

^{Written by Cursor Bugbot for commit 6fc0511. This will update automatically on new commits. Configure here.}

[Mercy811]

LGTM!

[Mercy811]

Synced offline. We merged this PR despite of the failed "Continuous Integration (Nx) / Check Deprecated Packages (pull_request)" as it's intended to update client-common