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.go

@@ -0,0 +1,21 @@
+package model
+
+// IngressKeyProtocol distinguishes OpenAI-compatible text APIs from Replicate-compatible image APIs.
+type IngressKeyProtocol string
+
+const (
+	IngressProtocolText  IngressKeyProtocol = "text"
+	IngressProtocolImage IngressKeyProtocol = "image"
+)
+
+func (p IngressKeyProtocol) Valid() bool {
+	return p == IngressProtocolText || p == IngressProtocolImage
+}
+
+// EffectiveProtocol returns text for legacy rows without an explicit protocol.
+func (k IngressKey) EffectiveProtocol() IngressKeyProtocol {
+	if k.Protocol == "" {
+		return IngressProtocolText
+	}
+	return k.Protocol
+}