fix: add static file serving with custom middleware

- Replaced wai-app-static with lightweight inline static file server
- Static files served from frontend/static/ under /static/ path
- Fixed ByteString/FilePath type mismatches for GHC 9.10
- Verified: CSS, manifest, login, signup, dashboard all HTTP 200

app/Main.hs

@@ -1,15 +1,20 @@
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TypeOperators #-}
-{-# OPTIONS_GHC -Wno-unused-imports -Wno-missing-export-lists #-}
+{-# OPTIONS_GHC -Wno-unused-imports -Wno-missing-export-lists -Wno-name-shadowing #-}
 
 module Main where
 
+import Data.ByteString.Char8 qualified as C8
+import Data.ByteString qualified as BS
+import Data.ByteString.Lazy qualified as BL
 import Effectful
-import Network.Wai.Application.Static qualified as Static
+import Network.HTTP.Types qualified as HTTP
+import Network.Wai qualified as Wai
 import Network.Wai.Handler.Warp qualified as Warp
-import System.Directory (createDirectoryIfMissing)
+import System.Directory (createDirectoryIfMissing, doesFileExist)
 import System.FilePath (takeDirectory)
+import Data.List (isSuffixOf)
 
 import Sis.Database
 import Sis.Page.Activity
@@ -26,6 +31,16 @@ import Web.Hyperbole.Effect.Response
 import Web.Hyperbole.Page
 import Web.Hyperbole.Route
 
+-- Simple MIME type resolver for static files
+mimeType :: FilePath -> BS.ByteString
+mimeType fp
+    | ".css" `isSuffixOf` fp = "text/css"
+    | ".js" `isSuffixOf` fp = "application/javascript"
+    | ".json" `isSuffixOf` fp = "application/json"
+    | ".png" `isSuffixOf` fp = "image/png"
+    | ".svg" `isSuffixOf` fp = "image/svg+xml"
+    | otherwise = "application/octet-stream"
+
 main :: IO ()
 main = do
     let dbPath = "data/sis.db"
@@ -37,14 +52,32 @@ main = do
     let port = 8080
     putStrLn $ "[sis] listening on 0.0.0.0:" <> show port
 
-    let app = liveAppWith
-                (ServerOptions
+    let hyperboleApp =
+            liveAppWith
+                ( ServerOptions
                     { toDocument = document documentHead
                     , serverError = defaultError
                     , parseRequestBody = defaultParseRequestBodyOptions
-                    })
+                    }
+                )
                 (runDB conn $ routeRequest router)
-    Warp.run port $ app
+
+    -- Serve static files under /static/, fall through to Hyperbole app
+    let staticDir = "frontend/static"
+    Warp.run port $ \req respond -> do
+        let rawPath = Wai.rawPathInfo req
+        if "/static/" `BS.isPrefixOf` rawPath
+            then do
+                let relPath = C8.unpack (C8.drop (C8.length "/static") rawPath)
+                    filePath = staticDir ++ relPath
+                exists <- doesFileExist filePath
+                if exists
+                    then do
+                        content <- BS.readFile filePath
+                        let ct = mimeType filePath
+                        respond $ Wai.responseLBS HTTP.status200 [("Content-Type", ct)] (BL.fromStrict content)
+                    else respond $ Wai.responseLBS HTTP.status404 [] "File not found"
+            else hyperboleApp req respond
 
 router :: (Hyperbole :> es, DB :> es, IOE :> es) => AppRoute -> Eff es Response
 router Home = do