Update AGENTS.md to include testing and execution commands

AGENTS.md

@@ -84,6 +84,34 @@ most important change points.
   directory.
 - `users.db` is stored at the working directory root.
 
+## Execution and Testing
+
+- .NET SDK: 8.x (`net8.0` for all projects).
+- Build from the repo root:
+
+```bash
+dotnet build OF DL.sln
+```
+
+- Run from source (runtime files are read from the current working directory):
+
+```bash
+dotnet run --project "OF DL/OF DL.csproj"
+```
+
+- If you want a local `rules.json` fallback, run from `OF DL/` or copy `OF DL/rules.json` into your working directory.
+- Run tests:
+
+```bash
+dotnet test "OF DL.Tests/OF DL.Tests.csproj"
+```
+
+- Optional coverage (coverlet collector):
+
+```bash
+dotnet test "OF DL.Tests/OF DL.Tests.csproj" --collect:"XPlat Code Coverage"
+```
+
 ## Authentication Flow
 
 - Auth data is stored in `auth.json` using the `Auth` model in `OF DL.Core/Models/Auth/Auth.cs`.