Recipe detail page with server-side HTML rendering

- Add Roux.Html.recipePage: full recipe detail page with:
  - Back navigation link
  - Title and metadata (servings, times, difficulty, etc.)
  - Ingredients summary list with quantities
  - Sections with named headings
  - Steps with inline element rendering:
    - Ingredients highlighted in pumpkin (with quantity badge)
    - Cookware in violet italic
    - Timers in azure with ⏱ icon
    - Comments in sand italic
    - Recipe refs as links
    - Line breaks
- Update Roux.Server: route /recipes/FILENAME to recipe page
  - Case-insensitive filename lookup, .cook extension optional
  - URL decoding for filenames
- Fix ingredient name parsing: restrict name characters to
  alphaNum + spaces/hyphens/apostrophes, preventing greedy
  consumption across special chars like ) and #
- Split name chars into pMultiNameChar (with spaces, before braces)
  and pSingleNameChar (without spaces, fallback)
- Suppress -Wname-shadowing in Html.hs (blaze-html exports clash
  with common variable names)
- All 26 tests passing, server smoke-tested with examples

src/Roux/Server.hs

@@ -1,7 +1,8 @@
+{-# LANGUAGE OverloadedStrings #-}
+
 {- | WAI application for the Roux recipe server.
 
-Handles HTTP requests directly via wai — no framework.  Currently serves
-a single index page listing all discovered recipes.
+Handles HTTP requests directly via wai — no framework.
 -}
 module Roux.Server (
     app,
@@ -9,6 +10,9 @@ module Roux.Server (
 
 import Control.Monad (when)
 import Data.ByteString.Lazy (ByteString)
+import Data.Char (toLower)
+import Data.List (find)
+import Data.Text (Text)
 import qualified Network.HTTP.Types as HTTP
 import qualified Network.Wai as Wai
 
@@ -31,7 +35,6 @@ app recipeDir = do
     when (errs > 0) $
         putStrLn $
             "[roux] " <> show errs <> " had parse errors"
-    -- Return the application; recipes are captured in the closure.
     pure (handleRequest recipes)
 
 -- | Route an incoming request to the appropriate handler.
@@ -39,8 +42,30 @@ handleRequest :: [Idx.RecipeInfo] -> Wai.Application
 handleRequest recipes request respond =
     case Wai.pathInfo request of
         [] -> respond (htmlResponse (Html.indexPage recipes))
+        ["recipes", rawPath] ->
+            case lookupRecipe (urlDecodePath rawPath) recipes of
+                Just info -> respond (htmlResponse (Html.recipePage info))
+                Nothing -> respond notFound
         _ -> respond notFound
 
+-- | Look up a recipe by filename (case-insensitive, .cook extension optional).
+lookupRecipe :: FilePath -> [Idx.RecipeInfo] -> Maybe Idx.RecipeInfo
+lookupRecipe target recipes =
+    let normalised = map toLower (stripCookExt target)
+     in find (\(Idx.RecipeInfo fp _ _) -> map toLower (stripCookExt fp) == normalised) recipes
+
+-- | Strip the .cook extension if present.
+stripCookExt :: FilePath -> FilePath
+stripCookExt fp
+    | ".cook" `isSuffixOf` fp = take (length fp - 5) fp
+    | otherwise = fp
+  where
+    isSuffixOf suffix s = suffix == drop (length s - length suffix) s
+
+-- | Decode a percent-encoded URL path segment to a FilePath.
+urlDecodePath :: Text -> FilePath
+urlDecodePath = Html.urlDecode
+
 -- | Build a 200 HTML response.
 htmlResponse :: ByteString -> Wai.Response
 htmlResponse body =