chore(ci): Add vira configuration

.gitignore

@@ -1,6 +1,6 @@
 .direnv
 # created when `just test <service>` is used
-/result
+/**/result
 # created when `just run <service>` is used
 /test/data
 

vira.hs

@@ -0,0 +1,21 @@
+-- CI configuration <https://vira.nixos.asia/>
+\ctx pipeline ->
+  let
+    isMaster = ctx.branch == "main"
+  in pipeline
+     { build.systems =
+        [ "x86_64-linux"
+        , "aarch64-darwin"
+        ]
+     , build.flakes =
+         [ "./example/simple" { overrideInputs = [("services-flake", ".")] }
+         , "./example/llm" { overrideInputs = [("services-flake", ".")] }
+         , "./example/share-services/pgweb" { overrideInputs = [("services-flake", "."), ("northwind", "path:./example/share-services/northwind")] }
+         , "./example/without-flake-parts" { overrideInputs = [("services-flake", ".")] }
+         , "./test" { overrideInputs = [("services-flake", ".")] }
+         , "./dev" { overrideInputs = [("services-flake", ".")] }
+         , "./doc"
+         ]
+     , signoff.enable = True
+     , cache.url = if isMaster then Just "https://cache.nixos.asia/oss" else Nothing
+     }