Store a target's settings as columns (closes #543)

A target's settings move from the per-type JSON string in
targets.config to columns: url, headers, timeout_seconds,
forward_query, archive_expiry and archive_rotation. A column a type
does not use stays empty. headers holds the header map as JSON text
through GORM's JSON serializer, and archive_expiry holds a
time.Duration, 0 meaning never. The forms check each setting once,
with the same refusals and messages, and the edit form is filled from
the columns, so the per-type config structs, their parsers and the
"could not be read" branches are gone. A delivery task carries the
six settings in place of the JSON string; tests check that each copy
into a task, and back out of one, keeps all six.

Model: opus-5-5

internal/delivery/engine.go

@@ -105,12 +105,19 @@ type Task struct {
 	WebhookID    string
 	EntrypointID string
 
-	TargetID     string
-	TargetName   string
-	TargetType   database.TargetType
-	TargetConfig string
-	MaxAttempts  int
+	// The target's fields, as they were when the task was made.
+	TargetID        string
+	TargetName      string
+	TargetType      database.TargetType
+	TargetURL       string
+	TargetHeaders   map[string]string
+	TimeoutSeconds  int
+	ForwardQuery    bool
+	ArchiveExpiry   time.Duration
+	ArchiveRotation string
+	MaxAttempts     int
 
+	// The event's fields.
 	Method      string
 	RawQuery    string
 	Headers     string
@@ -1543,10 +1550,15 @@ func buildEventFromTask(task *Task) database.Event {
 
 func buildTargetFromTask(task *Task) database.Target {
 	target := database.Target{
-		Name:        task.TargetName,
-		Type:        task.TargetType,
-		Config:      task.TargetConfig,
-		MaxAttempts: task.MaxAttempts,
+		Name:            task.TargetName,
+		Type:            task.TargetType,
+		URL:             task.TargetURL,
+		Headers:         task.TargetHeaders,
+		TimeoutSeconds:  task.TimeoutSeconds,
+		ForwardQuery:    task.ForwardQuery,
+		ArchiveExpiry:   task.ArchiveExpiry,
+		ArchiveRotation: task.ArchiveRotation,
+		MaxAttempts:     task.MaxAttempts,
 	}
 
 	target.ID = task.TargetID
@@ -1825,21 +1837,26 @@ func buildRecoveryTask(
 	}
 
 	return Task{
-		DeliveryID:   d.ID,
-		EventID:      d.EventID,
-		WebhookID:    webhookID,
-		EntrypointID: event.EntrypointID,
-		TargetID:     target.ID,
-		TargetName:   target.Name,
-		TargetType:   target.Type,
-		TargetConfig: target.Config,
-		MaxAttempts:  target.MaxAttempts,
-		Method:       event.Method,
-		RawQuery:     event.RawQuery,
-		Headers:      event.Headers,
-		ContentType:  event.ContentType,
-		Body:         bodyPtr,
-		AttemptNum:   attemptNum,
+		DeliveryID:      d.ID,
+		EventID:         d.EventID,
+		WebhookID:       webhookID,
+		EntrypointID:    event.EntrypointID,
+		TargetID:        target.ID,
+		TargetName:      target.Name,
+		TargetType:      target.Type,
+		TargetURL:       target.URL,
+		TargetHeaders:   target.Headers,
+		TimeoutSeconds:  target.TimeoutSeconds,
+		ForwardQuery:    target.ForwardQuery,
+		ArchiveExpiry:   target.ArchiveExpiry,
+		ArchiveRotation: target.ArchiveRotation,
+		MaxAttempts:     target.MaxAttempts,
+		Method:          event.Method,
+		RawQuery:        event.RawQuery,
+		Headers:         event.Headers,
+		ContentType:     event.ContentType,
+		Body:            bodyPtr,
+		AttemptNum:      attemptNum,
 	}
 }