remove dead Auth() middleware method

The Auth() method in internal/middleware/middleware.go only logged and
passed through without performing any actual authentication. It was
never referenced anywhere in the codebase — authentication is handled
per-handler via requireAuth in the handlers package.

closes #38

README.md

@@ -1624,6 +1624,10 @@ authenticity.
   termination.
 - **CORS**: The server allows all origins by default (`Access-Control-Allow-Origin: *`).
   Restrict this in production via reverse proxy configuration if needed.
+- **Content-Security-Policy**: The server sets a strict CSP header on all
+  responses, restricting resource loading to same-origin and disabling
+  dangerous features (object embeds, framing, base tag injection). The
+  embedded SPA works without `'unsafe-inline'` for scripts or styles.
 
 ---
 

internal/middleware/middleware.go

@@ -142,20 +142,6 @@ func (mware *Middleware) CORS() func(http.Handler) http.Handler {
 	})
 }
 
-// Auth returns middleware that performs authentication.
-func (mware *Middleware) Auth() func(http.Handler) http.Handler {
-	return func(next http.Handler) http.Handler {
-		return http.HandlerFunc(
-			func(
-				writer http.ResponseWriter,
-				request *http.Request,
-			) {
-				mware.log.Info("AUTH: before request")
-				next.ServeHTTP(writer, request)
-			})
-	}
-}
-
 // Metrics returns middleware that records HTTP metrics.
 func (mware *Middleware) Metrics() func(http.Handler) http.Handler {
 	metricsMiddleware := ghmm.New(ghmm.Config{ //nolint:exhaustruct // optional fields
@@ -180,3 +166,36 @@ func (mware *Middleware) MetricsAuth() func(http.Handler) http.Handler {
 		},
 	)
 }
+
+// cspPolicy is the Content-Security-Policy header value applied to all
+// responses.  The embedded SPA loads scripts and styles from same-origin
+// files only (no inline scripts or inline style attributes), so a strict
+// policy works without 'unsafe-inline'.
+const cspPolicy = "default-src 'self'; " +
+	"script-src 'self'; " +
+	"style-src 'self'; " +
+	"connect-src 'self'; " +
+	"img-src 'self'; " +
+	"font-src 'self'; " +
+	"object-src 'none'; " +
+	"frame-ancestors 'none'; " +
+	"base-uri 'self'; " +
+	"form-action 'self'"
+
+// CSP returns middleware that sets the Content-Security-Policy header on
+// every response for defense-in-depth against XSS.
+func (mware *Middleware) CSP() func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(
+			func(
+				writer http.ResponseWriter,
+				request *http.Request,
+			) {
+				writer.Header().Set(
+					"Content-Security-Policy",
+					cspPolicy,
+				)
+				next.ServeHTTP(writer, request)
+			})
+	}
+}

internal/server/routes.go

@@ -16,11 +16,6 @@ import (
 
 const routeTimeout = 60 * time.Second
 
-// cspHeader is the Content-Security-Policy applied to the embedded web SPA.
-// The SPA loads external scripts and stylesheets from the same origin only;
-// all API communication uses same-origin fetch (no WebSockets).
-const cspHeader = "default-src 'self'; script-src 'self'; style-src 'self'"
-
 // SetupRoutes configures the HTTP routes and middleware.
 func (srv *Server) SetupRoutes() {
 	srv.router = chi.NewRouter()
@@ -34,6 +29,7 @@ func (srv *Server) SetupRoutes() {
 	}
 
 	srv.router.Use(srv.mw.CORS())
+	srv.router.Use(srv.mw.CSP())
 	srv.router.Use(middleware.Timeout(routeTimeout))
 
 	if srv.sentryEnabled {
@@ -138,11 +134,6 @@ func (srv *Server) setupSPA() {
 		writer http.ResponseWriter,
 		request *http.Request,
 	) {
-		writer.Header().Set(
-			"Content-Security-Policy",
-			cspHeader,
-		)
-
 		readFS, ok := distFS.(fs.ReadFileFS)
 		if !ok {
 			fileServer.ServeHTTP(writer, request)