feat: add DID-based authentication middleware

pkg/common/didauth/producer/context.go

@@ -0,0 +1,20 @@
+package producer
+
+import (
+	"github.com/labstack/echo/v4"
+	"github.com/onsonr/sonr/crypto/ucan"
+	"github.com/onsonr/sonr/crypto/ucan/store"
+	"github.com/onsonr/sonr/pkg/common/ipfs"
+)
+
+type ProducerContext struct {
+	echo.Context
+	// TokenParser is the attentuations assigned to the producer service
+	TokenParser *ucan.TokenParser
+
+	// TokenStore is the token store used to store and retrieve tokens
+	TokenStore store.IPFSTokenStore
+
+	// IPFSClient is the IPFS client used to resolve the UCAN
+	IPFSClient ipfs.Client
+}