docs: Prune documentation - DRY versioning, split roadmap

- Split roadmap into dedicated ROADMAP.md (links to phoebe tasks)
- Prune Endgame-Vision.md: roadmap section, links section, version history
- Standardize version footers: one-line format across 17+ files
- Add Navigation section pointing to README.md for file index

Pattern: **Version:** X.Y | **Created:** YYYY-MM-DD | **Updated:** YYYY-MM-DD

Git is the changelog. Philosophy quotes preserved.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

architecture/Nimmerversity.md

@@ -581,10 +581,6 @@ Then:
 
 ---
 
-**Created**: 2025-12-05
-**Updated**: 2025-12-06 (multilingual triangulation)
-**Promoted**: 2025-12-29 (from archive, major v2.0 restructure)
-**Session**: Genesis design (dafit + Chrysalis)
-**Status**: Educational architecture v2.0 — Multimodal Polymath
+**Version:** 2.0 | **Created:** 2025-12-05 | **Updated:** 2025-12-29
 
 🎓🌱📚 *The school is ready. The student approaches.*