[tianxiaochannel-oss88]

Summary

• replace the README architecture diagram with a product-level view of client surfaces, the local daemon, workspace policy, runtime supervision, providers, tools, and durable evidence;
• add a 1280x640 GitHub Social Preview asset at docs/design/assets/ling-stack-social-preview.png using the Ling Stack mark and current product positioning;
• keep the detailed implementation architecture in docs/architecture.md;
• avoid presenting the outdated concept screenshots as current product evidence.

Social Preview

After the repository is public and the GitHub setting is available, upload docs/design/assets/ling-stack-social-preview.png from Settings -> General -> Social preview. The image is intended for link previews in chat, issue trackers, and social platforms; it does not replace the account avatar or repository favicon.

Validation

• corepack pnpm check:docs -> passed
• corepack pnpm check:licenses -> passed before the asset-only commit
• corepack pnpm check:public -> passed
• git diff --check -> passed
• PNG dimensions -> 1280x640

Scope

README and repository asset only. GitHub repository metadata changes (description, topics, and delete-branch-on-merge) were applied separately.