make sidecar a SDK, agent won't feel anything about it.

refactor: extract SidecarClient SDK and fix string-enum revival bug

docs: update README and ARCHITECTURE for v2 features (snapshots + concurrent tasks)

feat(v2): snapshot checkpointing + trunk-based concurrent tasks

seperate the internal url call and external url call

Merge pull request #3 from xichen1997/seperate-infra-agent-design

update igt ignore

Merge pull request #2 from xichen1997/seperate-infra-agent-design

add integration tests for crash

Merge pull request #1 from xichen1997/seperate-infra-agent-design

udpate the unfinished tasks

add a demo inject crash in a long task

update README.md

new agent infra speration

add a new trace for example