Show a slack target's retry setting in the target list (closes #395)

A slack target's edit page offers Max Retries and the delivery engine honours it, but the target list showed only its masked webhook URL, so setting retries changed nothing visible. The list now shows a slack target's Max Retries line exactly as an http target's, from the one function both use, so the label and the "0 (fire-and-forget)" wording cannot drift apart. The Max Queue Size line stays on http targets only. Tests cover a slack target with retries set, and one with a queue size stored that shows no queue-size line.

Model: opus-5-5

internal/delivery/target_config_view_test.go

@@ -32,6 +32,7 @@ const (
 	viewMaskedOrigin  = viewExampleOrigin + "/..."
 	viewUnavailable   = "(unavailable)"
 	viewExpiryNever   = "never"
+	viewMaxRetries    = "Max Retries"
 )
 
 func TestMaskedWebhookURL(t *testing.T) {
@@ -157,9 +158,7 @@ func TestNewTargetViews_DeletedTarget(t *testing.T) {
 		t, slackTargetName+" (deleted)", view.DisplayName(),
 	)
 	assert.Equal(
-		t,
-		map[string]string{"Webhook URL": slackMaskedURL},
-		fieldMap(view.Config),
+		t, viewFor(t, slackTarget()).Config, view.Config,
 	)
 }
 
@@ -189,7 +188,32 @@ func TestNewTargetViews_Slack(t *testing.T) {
 
 	assert.Equal(
 		t,
-		map[string]string{"Webhook URL": slackMaskedURL},
+		map[string]string{
+			"Webhook URL":  slackMaskedURL,
+			viewMaxRetries: "0 (fire-and-forget)",
+		},
+		fieldMap(view.Config),
+	)
+}
+
+// TestNewTargetViews_SlackRetries proves a Slack target shows
+// its retry count the same way an HTTP target does, and no
+// queue size even when one is stored: delivery never reads it.
+func TestNewTargetViews_SlackRetries(t *testing.T) {
+	t.Parallel()
+
+	target := slackTarget()
+	target.MaxRetries = 2
+	target.MaxQueueSize = 100
+
+	view := viewFor(t, target)
+
+	assert.Equal(
+		t,
+		map[string]string{
+			"Webhook URL":  slackMaskedURL,
+			viewMaxRetries: "2",
+		},
 		fieldMap(view.Config),
 	)
 }
@@ -214,7 +238,7 @@ func TestNewTargetViews_HTTP(t *testing.T) {
 			"Destination URL": viewMaskedOrigin,
 			"Timeout":         "30s",
 			"Headers":         "1 configured",
-			"Max Retries":     "5",
+			viewMaxRetries:    "5",
 			"Max Queue Size":  "100",
 		},
 		fields,
@@ -238,7 +262,7 @@ func TestNewTargetViews_HTTPFireAndForget(t *testing.T) {
 		t,
 		map[string]string{
 			"Destination URL": viewMaskedOrigin,
-			"Max Retries":     "0 (fire-and-forget)",
+			viewMaxRetries:    "0 (fire-and-forget)",
 		},
 		fieldMap(view.Config),
 	)