feat!: consume privilege events with go-messaging-amqp

eventsourced and sloth moved to Codeberg, where their AMQP modules use codeberg.org/messaging/go-messaging-amqp instead of goamqp; services migrating to them need authz_client on the same client. Setup() now returns go-messaging-amqp setups: the same four per-replica (transient) consumers, with typed handlers that feed Process.

BREAKING CHANGE: Setup returns go-messaging-amqp setups, and Process(msg any) error replaces Process(msg, goamqp.Headers) (any, error). Services stay on v0.5.x until they migrate (see docs/design/codeberg-migration.md).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SV1epy2pKvBx3yDfhxATk2

client.go

@@ -1,6 +1,7 @@
 package client
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -8,7 +9,8 @@ import (
 	"reflect"
 	"sync"
 
-	"github.com/sparetimecoders/goamqp"
+	goamqp "codeberg.org/messaging/go-messaging-amqp"
+	spec "codeberg.org/messaging/messaging"
 )
 
 // CompanyPrivileges contains the privileges for a combination of email address and company id
@@ -95,15 +97,22 @@ func (h *PrivilegeHandler) Fetch() error {
 
 func (h *PrivilegeHandler) Setup() []goamqp.Setup {
 	return []goamqp.Setup{
-		goamqp.TransientEventStreamConsumer("User.Added", h.Process, UserAdded{}),
-		goamqp.TransientEventStreamConsumer("User.Removed", h.Process, UserRemoved{}),
-		goamqp.TransientEventStreamConsumer("Privilege.Added", h.Process, PrivilegeAdded{}),
-		goamqp.TransientEventStreamConsumer("Privilege.Removed", h.Process, PrivilegeRemoved{}),
+		goamqp.TransientEventStreamConsumer("User.Added", process[UserAdded](h)),
+		goamqp.TransientEventStreamConsumer("User.Removed", process[UserRemoved](h)),
+		goamqp.TransientEventStreamConsumer("Privilege.Added", process[PrivilegeAdded](h)),
+		goamqp.TransientEventStreamConsumer("Privilege.Removed", process[PrivilegeRemoved](h)),
+	}
+}
+
+// process adapts Process to a typed go-messaging-amqp handler.
+func process[T any](h *PrivilegeHandler) spec.EventHandler[T] {
+	return func(_ context.Context, event spec.ConsumableEvent[T]) error {
+		return h.Process(&event.Payload)
 	}
 }
 
 // Process privilege-related events and update the internal state
-func (h *PrivilegeHandler) Process(msg interface{}, _ goamqp.Headers) (interface{}, error) {
+func (h *PrivilegeHandler) Process(msg any) error {
 	h.Lock()
 	defer h.Unlock()
 
@@ -116,21 +125,21 @@ func (h *PrivilegeHandler) Process(msg interface{}, _ goamqp.Headers) (interface
 				ev.CompanyID: {},
 			}
 		}
-		return nil, nil
+		return nil
 	case *UserRemoved:
 		if priv, exists := h.privileges[ev.Email]; exists {
 			delete(priv, ev.CompanyID)
 		}
-		return nil, nil
+		return nil
 	case *PrivilegeAdded:
 		h.setPrivileges(ev.Email, ev.CompanyID, ev.Privilege, true)
-		return nil, nil
+		return nil
 	case *PrivilegeRemoved:
 		h.setPrivileges(ev.Email, ev.CompanyID, ev.Privilege, false)
-		return nil, nil
+		return nil
 	default:
 		fmt.Printf("Got unexpected message type (%s): '%+v'\n", reflect.TypeOf(msg).String(), msg)
-		return nil, fmt.Errorf("unexpected event type: '%s'", reflect.TypeOf(msg))
+		return fmt.Errorf("unexpected event type: '%s'", reflect.TypeOf(msg))
 	}
 }