feat(fsharp): m01-m06 util, model, rules, random, spawn, game, view with Expecto tests

Co-Authored-By: Claude Opus 5.5 <[email protected]>

fsharp/solutions/Spawn.fs

@@ -0,0 +1,25 @@
+/// m04 spawn: placing apples with the Random from Random.fs.
+module Snake.Spawn
+
+open Snake.Model
+
+let freeCells (state: GameState) : Point list =
+    [ for y in Util.range state.Height do
+          for x in Util.range state.Width do
+              let p = { X = x; Y = y }
+              if not (Util.contains state.Snake p (=)) then
+                  yield p ]
+
+let spawnApple (state: GameState) : GameState =
+    if state.Apple.IsSome || state.Status <> Playing then
+        state
+    else
+        match freeCells state with
+        | [] -> { state with Status = Won }
+        | cells ->
+            let i, seed = Random.run state.Seed (Random.intBelow (List.length cells))
+            { state with Apple = Some(List.item i cells); Seed = seed }
+
+let tick (state: GameState) : GameState = spawnApple (Rules.advance state)
+
+let newGame (seed: uint32) : GameState = spawnApple (initialState seed)