docs(project): define roadmap issue workflow and changelog policy #6

Problem

Public roadmap and shipped changelog need a consistent maintenance workflow.

Goal

Standardize:

• README as public roadmap
• GitHub Issues as execution tracker
• FEATURES.md as shipped changelog / feature registry
• GitHub Releases as versioned milestone summaries

Requirements

• roadmap items should link to issues
• shipped items should move to FEATURES.md
• issues should use consistent labels

Suggested labels

• roadmap
• enhancement
• area labels like agent, tui, docs, interop, website

Acceptance criteria

• contributors know where to add upcoming work
• contributors know where to record shipped work
• contributors know where release notes belong
  EOF