Add minimal Cooklang parser with first tests

- Create Roux.Parser with parseCookFile (splits paragraphs, treats
  each as a plain-text step, no metadata parsing yet)
- Add emptyMetadata to Roux.Types for convenience
- Add test dependencies: hspec, tasty-golden, tasty-hspec
- Add ParserSpec with 4 tests covering single step, multiple steps,
  empty input, and whitespace trimming
- Wire ParserSpec into test runner via tasty-hspec

test/Roux/ParserSpec.hs

@@ -0,0 +1,73 @@
+module Roux.ParserSpec (spec) where
+
+import Data.List.NonEmpty (NonEmpty ((:|)))
+import Test.Hspec (Spec, describe, it, shouldBe)
+
+import Roux.Parser (parseCookFile)
+import Roux.Types
+
+spec :: Spec
+spec =
+    describe "parseCookFile" $ do
+        it "parses a single step of plain text" $ do
+            let input = "Hello, world."
+                expected =
+                    Right Recipe
+                        { recipeMetadata = emptyMetadata
+                        , recipeSections =
+                            Section
+                                { sectionName = Nothing
+                                , sectionSteps =
+                                    Step
+                                        { unStep = [StepText "Hello, world."]
+                                        }
+                                        :| []
+                                }
+                                :| []
+                        }
+            parseCookFile input `shouldBe` expected
+
+        it "parses multiple steps separated by a blank line" $ do
+            let input = "Wash the potatoes.\n\nPeel and dice them."
+                expected =
+                    Right Recipe
+                        { recipeMetadata = emptyMetadata
+                        , recipeSections =
+                            Section
+                                { sectionName = Nothing
+                                , sectionSteps =
+                                    Step {unStep = [StepText "Wash the potatoes."]}
+                                        :| [ Step {unStep = [StepText "Peel and dice them."]}
+                                           ]
+                                }
+                                :| []
+                        }
+            parseCookFile input `shouldBe` expected
+
+        it "handles empty input by returning an empty recipe" $ do
+            let expected =
+                    Right Recipe
+                        { recipeMetadata = emptyMetadata
+                        , recipeSections =
+                            Section
+                                { sectionName = Nothing
+                                , sectionSteps = Step {unStep = []} :| []
+                                }
+                                :| []
+                        }
+            parseCookFile "" `shouldBe` expected
+
+        it "trims leading and trailing whitespace from each step" $ do
+            let input = "\n\n  Mix well.  \n\n"
+                expected =
+                    Right Recipe
+                        { recipeMetadata = emptyMetadata
+                        , recipeSections =
+                            Section
+                                { sectionName = Nothing
+                                , sectionSteps =
+                                    Step {unStep = [StepText "Mix well."]} :| []
+                                }
+                                :| []
+                        }
+            parseCookFile input `shouldBe` expected