Consolidate spatial docs into universe model

docs/DESIGN.md

@@ -15,11 +15,6 @@ For the implementation migration path from the current codebase to this design s
   - intra-system warp and inter-system FTL
   - viewer hierarchy and simulation boundaries
 
-- [SPACES.md](/home/jbourdon/repos/space-game/docs/SPACES.md)
-  - older spatial design document
-  - useful migration context, but secondary to `UNIVERSE-MODEL.md`
-  - should be aligned to the universe model over time
-
 - [COMMANDERS.md](/home/jbourdon/repos/space-game/docs/COMMANDERS.md)
   - commander roles for factions, stations, and ships
   - command hierarchy
@@ -64,7 +59,7 @@ For the implementation migration path from the current codebase to this design s
   - policy-based behavior limits
 
 - [COMBAT.md](/home/jbourdon/repos/space-game/docs/COMBAT.md)
-  - local-space combat
+  - localspace combat
   - piracy and station defense
   - claim destruction and contest
   - commander-driven engagement behavior
@@ -95,7 +90,7 @@ For the implementation migration path from the current codebase to this design s
 
 - [STATIONS.md](/home/jbourdon/repos/space-game/docs/STATIONS.md)
   - station roles
-  - local bubble functions
+  - localspace functions
   - station command requirements
   - station services, docking, and market responsibilities