Roadmap items for version 0.2

[zhangfengcdt]

No description provided.

[Copilot]

Pull Request Overview

Updates the README to include new roadmap items for versions 0.2.1 and 0.2.2 and refines the Use Cases section.

• Clarified Use Cases by renaming and de-duplicating a “Version Control” entry.
• Added a 0.2.1 roadmap with diff/merge and history features.
• Introduced a 0.2.2 roadmap covering version-controlled and decentralized database support.

Comments suppressed due to low confidence (2)

README.md:191

• The '+-' merged diff prefix here leads to invalid Markdown bullet syntax. Change it to a single '-' for the list item and ensure it aligns under the 'Version 0.2.1' heading.

- [ ] tree diffing and merging

README.md:197

• Nested items under the 0.2.2 section use inconsistent indentation. Standardize indentation (e.g., two or four spaces) for all sub-bullets to improve readability and uniformity.

  - [ ] prolly tree backend for git databases using `gitoxide` crate