twitter: migrate from OAuth 1.0a to OAuth 2.0

X/Twitter is sunsetting OAuth 1.0a. The `twitter` app uses OAuth 1.0a for all requests via the `oauth-1.0a` package. When OAuth 1.0a is sunset, all 13 actions and 11 sources will stop working.

The `upload-media` action has a separate dependency on the v1.1 API (`upload.twitter.com/1.1`) that will also break.

Users on X's Free plan are already hitting 403s on `GET /2/users/me`. This endpoint is called on every action that needs the authenticated user's ID, and on all sources. The Free plan restricts most v2 endpoints beyond `POST /2/tweets`.

The fix requires migrating the app to OAuth 2.0 (PKCE). The Pipedream app registration for Twitter will need to be updated alongside the component changes, and all connected accounts will need to re-authorize.

OAuth 2.0 scopes needed: `tweet.read`, `tweet.write`, `users.read`, `follows.read`, `follows.write`, `like.read`, `like.write`, `dm.read`, `dm.write`, `list.read`, `list.write`, `offline.access`

**Ref:** [OAuth 2.0 Authorization Code Flow with PKCE — X API docs](https://docs.x.com/resources/fundamentals/authentication/oauth-2-0/authorization-code)