Proposal: Move diff, bundler, and optimizer into CLI

As part of the 2026 community goals (more details here: https://github.com/asyncapi/community/issues/3495), we conducted an audit of all repositories. The summary of the findings can be found here: https://github.com/asyncapi/community/issues/3495#issuecomment-4681625773.

As suggested by @deberg, we are proposing to move the `diff`, `bundler`, and `optimizer` repositories to the CLI repository.

Reference to the conversation:
- https://asyncapi.slack.com/archives/C34F2JV0U/p1774973085382029?thread_ts=1774874525.585229&cid=C34F2JV0U
- https://github.com/asyncapi/community/issues/3495

I am opening this issue to gather feedback and approval from the code owners of this repository regarding the proposal to move this repository to CLI.

Tagging all code owners for their feedback and approval.
@aayushmau5 @magicmatatjahu @derberg

Read the linked community audit and the referenced discussion first, then review the diff repository context and gather feedback from the tagged code owners. Done means the proposal has a documented approval or decision on whether to move diff, bundler, and optimizer into the CLI repository.

Written by the indexing model from the issue text.