chore(copilot): add basic Copilot instructions

Author: xperiandri

.github/copilot-instructions.md

@@ -0,0 +1,57 @@
+We prefer the latest F# 9 features over the old syntax
+
+Prefer `voption` over `option`
+
+Prefer `task` CE over `async` CE
+
+This is how you define a non-default F# class constructor:
+```fsharp
+type DerivedClass =
+    inherit BaseClass
+
+    new (``arguments here``) as ``created object``
+        =
+        // create any objects used in the base class constructor
+        let fieldValue = ""
+        {
+            inherit
+                BaseClass (``arguments here``)
+        }
+        then
+            ``created object``.otherField <- fieldValue
+
+    [<DefaultValue>]
+    val mutable otherField : FieldType
+```
+
+Always prefer F# class initializers over property assignment! **You absolutely must use F# class initializers instead of property assignment**!
+
+Class declaration:
+``` F#
+type MyClass (someConstructorParam : string) =
+    member ReadOnlyProperty = someConstructorParam
+
+    member val MutableProperty1 = "" with get, set
+    member val MutableProperty2 = "" with get, set
+```
+
+Wrong:
+``` F#
+let myClass = MyClass("some value")
+myClass.MutableProperty1 <- "new value"
+myClass.MutableProperty2 <- "new value"
+```
+
+Right:
+``` F#
+let myClass =
+    MyClass(
+        // constructor parameters go first without names
+        "some value",
+        // then mutable properties go next with names
+        MutableProperty1 = "new value",
+        MutableProperty2 =
+            // operations must be placed into parentheses
+            (5 |> string)
+    )
+```

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Remove `Newtonsoft.Json` NuGet dependency #725 [@xperiandri]
 - Add missing rule checks for FL0079-FL0081 #713 [@BennieCopeland]
 - Modify `.gitignore` to the Visual Studio standard one #735 [@xperiandri]
+- Add basic Copilot instructions and GitHub MCP #726 [@xperiandri]
 
 ## [0.24.2] - 2024-02-29