Refine anchor-first universe migration docs

docs/ROADMAP.md

@@ -73,7 +73,7 @@ Current state:
 
 Primary gaps:
 
-- [`RuntimeModels.cs`](/home/jbourdon/repos/space-game/apps/backend/Simulation/RuntimeModels.cs) has no `AnchorRuntime`, `LocalspaceRuntime`, `ClaimRuntime`, or `ConstructionSiteRuntime`.
+- [`RuntimeModels.cs`](/home/jbourdon/repos/space-game/apps/backend/Simulation/RuntimeModels.cs) has no first-class `AnchorRuntime` aligned with the target design, plus no fully anchor-native `ClaimRuntime` or `ConstructionSiteRuntime`.
 - [`ScenarioLoader.cs`](/home/jbourdon/repos/space-game/apps/backend/Simulation/ScenarioLoader.cs) computes station positions directly instead of creating anchor-backed placement.
 - [`SimulationEngine.cs`](/home/jbourdon/repos/space-game/apps/backend/Simulation/SimulationEngine.cs) still treats travel as raw coordinate movement rather than anchor-to-anchor transit between spaces.
 
@@ -247,7 +247,6 @@ Work:
 
 - extend [`RuntimeModels.cs`](/home/jbourdon/repos/space-game/apps/backend/Simulation/RuntimeModels.cs) with:
   - `AnchorRuntime`
-  - `LocalspaceRuntime`
   - `CommanderRuntime`
   - `ClaimRuntime`
   - `ConstructionSiteRuntime`
@@ -262,7 +261,6 @@ Work:
 - add structured ship spatial state:
   - current space layer
   - current anchor
-  - current localspace
   - current transit
 
 Why first: