docs(trivium): replace dream ladder with OAN terms

[Illian-Amerond]

Summary

• Replaces the internal dream / /Dream ladder with EC, OAN.Evolution, OAN.Ascension, OAN.Enlightenment, and SelfGEL.
• Adds the Git chamber workflow: issue, branch, PR, merge, tag/release when needed.
• Keeps dream language only as external comparison terminology and preserves public-safety boundaries.

Public-Safety Notes

• No private archive material, local paths, secrets, credentials, session logs, runtime state, or controlled residue are added.
• Groupoid language remains bounded as theoretical and methodological, not a public proof claim.
• SelfGEL admission remains separately gated and HITL-governed.

Refs #7