Release v0.2.8

• Review: Added a project-wide changes review mode alongside session diffs so you can inspect broader workspace edits from the review flow. (@isomoes)
• Sessions: Added timeline jump controls and review file toggles to make it easier to navigate conversation history and focus file review context. (@isomoes)
• Settings: Disabled update prompts and linked changelog entries from settings to reduce noise while making release notes easier to access. (@isomoes)
• Projects: Added a close-project command in the web app for faster project switching and cleanup. (@isomoes)
• Docs: Refreshed the README with a Bilibili video link and added architecture/hosted-flow documentation updates. (@isomoes)