Split ingress keys into text/image protocols with Replicate model listing.

Add model input defaults (including prompt), workflow model editing, ingress API docs, and fix img2img image upload filenames for signed URLs.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/model/ingress_protocol_test.go

@@ -0,0 +1,22 @@
+package model
+
+import "testing"
+
+func TestIngressKeyEffectiveProtocol(t *testing.T) {
+	if (IngressKey{}).EffectiveProtocol() != IngressProtocolText {
+		t.Fatal("empty protocol should default to text")
+	}
+	k := IngressKey{Protocol: IngressProtocolImage}
+	if k.EffectiveProtocol() != IngressProtocolImage {
+		t.Fatal("expected image protocol")
+	}
+}
+
+func TestIngressKeyProtocolValid(t *testing.T) {
+	if !IngressProtocolText.Valid() || !IngressProtocolImage.Valid() {
+		t.Fatal("text and image should be valid")
+	}
+	if IngressKeyProtocol("other").Valid() {
+		t.Fatal("unexpected valid protocol")
+	}
+}