docs: tighten the README prose

[cardmagic]

No description provided.

[greptile-apps]

Greptile Summary

This documentation-only PR tightens README prose without changing its technical meaning.

• Replaces figurative descriptions with direct statements about subsystem dependencies and identity-level serialization.
• Removes editorial asides from transaction guidance and delivery semantics.
• Preserves the documented at-least-once delivery and per-identity ordering guarantees.

Confidence Score: 5/5

The PR appears safe to merge because the revised prose remains consistent with the repository’s documented behavior.

No actionable correctness, security, documentation, or repository-rule violations were found in the changed wording.

Important Files Changed

Filename	Overview
README.md	Simplifies several explanatory passages while preserving the runtime’s documented concurrency and delivery contracts.

_{Reviews (1): Last reviewed commit: "docs: tighten the README prose" | Re-trigger Greptile}