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/Data-Architecture.md

@@ -641,9 +641,7 @@ ORDER BY n.nerve_name, dt.mode;
 
 ## 📍 Document Status
 
-**Version**: 4.0 (Layered State Machine Schema)
-**Created**: 2025-10-07 (original)
-**Updated v4**: 2025-12-07 (unified with Cellular-Architecture v4)
+**Version:** 4.0 | **Created:** 2025-10-07 | **Updated:** 2025-12-07
 
 **Key Changes from v3**:
 - ❌ 15 tables for competition metaphor