Update DOCUMENT-INDEX: mission-statement description + legacy-vision redirect

DOCUMENT-INDEX.md

@@ -60,7 +60,7 @@ root/
 | `migration-rollback.md` | `docs/planning/` | Migration complete |
 | `git-access-plan.md` | `docs/core/` | Fully implemented |
 | `what-claude-learned.md` | `docs/relationship/` | Merged into claude-relationship-context.md |
-| `legacy-vision.md` | `docs/relationship/` | Merged into mission-statement.md | and old documents
+| `legacy-vision.md` | `docs/relationship/` | Merged into `docs/planning/mission-statement.md` (see Legacy Vision section) |
 │       ├── 2026-02-09-consolidation/  ← Consolidated old docs
 │       └── sessions/                  ← Session archives by date
 │           ├── 2026-02-09/
@@ -144,7 +144,7 @@ root/
 
 | Path | Description |
 |:-----|:------------|
-| `mission-statement.md` | Firefrost Gaming mission statement |
+| `mission-statement.md` | FFG-PLN-001 — Firefrost Gaming mission statement & Legacy Vision (the deepest "why" we build) |
 | `path-philosophy.md` | The Path philosophy |
 | `design-bible.md` | Design bible (branding, aesthetics, Citadel/Obsidian) |
 | `subscription-tiers.md` | Subscription tier structure |