feat(httpauth-jwt): initial release — self-issued JWT auth middleware v1.0.0

Provides AuthMiddleware (calls httpauth.SetTokenData, accepts Verifier or Signer),
IssueTokenPair (access + refresh tokens as jwt.MapClaims, custom claims at top
level for ClaimsPermissionProvider compatibility), RefreshTokenPair (blacklist
check + rotation + re-issue), and Signer/Verifier implementations for HMAC-SHA256
and RSA-SHA256 including PEM loaders and a public-key-only Verifier for read-only
microservices.

auth.go

@@ -0,0 +1,62 @@
+package jwtauth
+
+import (
+	"net/http"
+	"path"
+	"strings"
+
+	"github.com/golang-jwt/jwt/v5"
+
+	httpauthmw "code.nochebuena.dev/go/httpauth"
+)
+
+// AuthMiddleware verifies the Bearer access token and injects uid + claims into
+// the request context via httpauth.SetTokenData. Downstream middleware
+// (EnrichmentMiddleware, AuthzMiddleware, ClaimsPermissionProvider) from
+// code.nochebuena.dev/go/httpauth reads them transparently.
+//
+// Accepts a Verifier — pass a Signer or a NewRSAPublicKeyVerifier depending on
+// whether the service issues tokens.
+//
+// Requests to publicPaths are skipped without token verification (wildcards
+// supported via path.Match). Returns 401 on missing, invalid, or expired tokens.
+func AuthMiddleware(verifier Verifier, publicPaths []string) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			for _, pattern := range publicPaths {
+				if matched, _ := path.Match(pattern, r.URL.Path); matched {
+					next.ServeHTTP(w, r)
+					return
+				}
+			}
+
+			authHeader := r.Header.Get("Authorization")
+			if !strings.HasPrefix(authHeader, "Bearer ") {
+				http.Error(w, "unauthorized", http.StatusUnauthorized)
+				return
+			}
+			tokenStr := strings.TrimPrefix(authHeader, "Bearer ")
+
+			token, err := verifier.Verify(tokenStr)
+			if err != nil {
+				http.Error(w, "unauthorized", http.StatusUnauthorized)
+				return
+			}
+
+			claims, ok := token.Claims.(jwt.MapClaims)
+			if !ok {
+				http.Error(w, "unauthorized", http.StatusUnauthorized)
+				return
+			}
+
+			uid, _ := claims["sub"].(string)
+			if uid == "" {
+				http.Error(w, "unauthorized", http.StatusUnauthorized)
+				return
+			}
+
+			ctx := httpauthmw.SetTokenData(r.Context(), uid, map[string]any(claims))
+			next.ServeHTTP(w, r.WithContext(ctx))
+		})
+	}
+}