Use local dotnet-ef tooling and strict EF migration checks

FAQ.md

@@ -30,6 +30,15 @@ To start with a clean backend state, stop the app and remove the corresponding S
 
 Usually no. Startup now uses EF Core migration-based schema upgrades (`Database.Migrate`) and applies pending migrations automatically.
 
+## How do I add a new EF migration in this repo?
+
+Use the repo-local tool manifest:
+
+```powershell
+dotnet tool restore
+dotnet dotnet-ef migrations add <MigrationName> --project RpgRoller/RpgRoller.csproj --startup-project RpgRoller/RpgRoller.csproj
+```
+
 ## Does the backend read SQLite on every API call?
 
 No. The backend loads state from SQLite once during startup into in-memory state and serves requests from memory. Successful state mutations are then written back to SQLite.