Web server with recipe index page

- Add Roux.Server: WAI application using wai+warp directly
  - Scans .cook files from recipe directory on startup
  - GET / → HTML index page listing all recipes
  - Other routes → 404
- Add Roux.RecipeIndex: directory scanning and recipe parsing
  - scanRecipes: lists .cook files, parses each, extracts titles
  - Falls back to filename when metadata title is absent
- Add Roux.Html: blaze-html rendering with Pico CSS
  - indexPage: renders recipe list with links
  - urlEncode: percent-encodes filenames for URLs
- Update Roux.hs: re-exports Server.app and Types
- Add filepath to dependencies

roux-server.cabal

@@ -17,7 +17,10 @@ build-type:     Simple
 library
   exposed-modules:
       Roux
+      Roux.Html
       Roux.Parser
+      Roux.RecipeIndex
+      Roux.Server
       Roux.Types
   other-modules:
       Paths_roux_server
@@ -36,6 +39,7 @@ library
     , bytestring
     , containers
     , directory
+    , filepath
     , http-types
     , optparse-applicative
     , parsec
@@ -64,6 +68,7 @@ executable roux-server
     , bytestring
     , containers
     , directory
+    , filepath
     , http-types
     , optparse-applicative
     , parsec
@@ -96,6 +101,7 @@ test-suite roux-server-test
     , bytestring
     , containers
     , directory
+    , filepath
     , hspec
     , http-types
     , optparse-applicative