fix(flow): support UUID model refs when provider filter is set

internal/conversation/flow/resolver.go

@@ -1585,7 +1585,7 @@ func (r *Resolver) selectChatModel(ctx context.Context, req conversation.ChatReq
 		return models.GetResponse{}, sqlc.LlmProvider{}, err
 	}
 	for _, m := range candidates {
-		if m.ModelID == modelID {
+		if matchesModelReference(m, modelID) {
 			prov, err := models.FetchProviderByID(ctx, r.queries, m.LlmProviderID)
 			if err != nil {
 				return models.GetResponse{}, sqlc.LlmProvider{}, err
@@ -1631,6 +1631,14 @@ resolved:
 	return model, prov, nil
 }
 
+func matchesModelReference(model models.GetResponse, modelRef string) bool {
+	ref := strings.TrimSpace(modelRef)
+	if ref == "" {
+		return false
+	}
+	return model.ID == ref || model.ModelID == ref
+}
+
 func (r *Resolver) listCandidates(ctx context.Context, providerFilter string) ([]models.GetResponse, error) {
 	var all []models.GetResponse
 	var err error

internal/conversation/flow/resolver_model_selection_test.go

@@ -0,0 +1,59 @@
+package flow
+
+import (
+	"testing"
+
+	"github.com/memohai/memoh/internal/models"
+)
+
+func TestMatchesModelReference_ModelID(t *testing.T) {
+	t.Parallel()
+
+	model := models.GetResponse{
+		ID:      "a55f0d2d-1547-49a0-b085-ec4ab778f4b8",
+		ModelID: "gpt-4o",
+	}
+
+	if !matchesModelReference(model, "gpt-4o") {
+		t.Fatal("expected model slug to match")
+	}
+}
+
+func TestMatchesModelReference_UUID(t *testing.T) {
+	t.Parallel()
+
+	model := models.GetResponse{
+		ID:      "a55f0d2d-1547-49a0-b085-ec4ab778f4b8",
+		ModelID: "gpt-4o",
+	}
+
+	if !matchesModelReference(model, "a55f0d2d-1547-49a0-b085-ec4ab778f4b8") {
+		t.Fatal("expected model UUID to match")
+	}
+}
+
+func TestMatchesModelReference_NoMatch(t *testing.T) {
+	t.Parallel()
+
+	model := models.GetResponse{
+		ID:      "a55f0d2d-1547-49a0-b085-ec4ab778f4b8",
+		ModelID: "gpt-4o",
+	}
+
+	if matchesModelReference(model, "gpt-4.1") {
+		t.Fatal("expected non-matching model reference to fail")
+	}
+}
+
+func TestMatchesModelReference_TrimmedInput(t *testing.T) {
+	t.Parallel()
+
+	model := models.GetResponse{
+		ID:      "a55f0d2d-1547-49a0-b085-ec4ab778f4b8",
+		ModelID: "gpt-4o",
+	}
+
+	if !matchesModelReference(model, "  gpt-4o  ") {
+		t.Fatal("expected trimmed model slug to match")
+	}
+}