[management] Let a discovery request name a record and a new upstream

Editing a provider's upstream URL meant retyping its API key. The key is the
one field the API never returns, so there was nothing to retype from, and the
dashboard had to demand it because a provider_id request resolved the upstream
from the stored row — listing the old endpoint while the form showed the new
one.

The request now reads as a partial edit of the record it names, the same way
PUT on a provider already does: an upstream in the body overrides the stored
one, an omitted upstream keeps it. The credential and the catalog entry still
come from the record only, so a caller cannot aim a stored key at a vendor of
their choosing.

management/internals/modules/agentnetwork/credentialcheck_test.go

@@ -456,3 +456,50 @@ func TestDiscoverProviderModels_SurfacesTheVendorRefusal(t *testing.T) {
 
 	require.EqualError(t, err, "the provider rejected the credential")
 }
+
+// TestDiscoverProviderModels_ListsAgainstTheUrlOnTheForm covers the edit the
+// operator cannot otherwise make: the upstream has been retyped and the
+// credential has not, because the API never returned it to be retyped. Naming
+// the record supplies the key; the request supplies the URL under test.
+func TestDiscoverProviderModels_ListsAgainstTheUrlOnTheForm(t *testing.T) {
+	ctx := context.Background()
+	f := newBootstrapFixture(t)
+	// Twice: the create, and the listing, which is gated on Create too.
+	f.expectPermission("account1", "user1", modules.AgentNetworkProviders, operations.Create, true)
+	f.expectPermission("account1", "user1", modules.AgentNetworkProviders, operations.Create, true)
+
+	created, err := f.manager.CreateProvider(ctx, "user1", newCheckedProvider("account1"))
+	require.NoError(t, err)
+	f.vendor.requests = nil
+
+	_, err = f.manager.DiscoverProviderModels(ctx, "account1", "user1", modeldiscovery.Request{
+		CatalogID:   "openai_api",
+		UpstreamURL: "https://gateway.example.com",
+	}, created.ID)
+	require.NoError(t, err)
+
+	asked := f.vendor.only(t)
+	require.Equal(t, "https://gateway.example.com", asked.UpstreamURL, "the typed url must be the one listed against")
+	require.Equal(t, "sk-good", asked.APIKey, "and the stored key must be what lists it")
+}
+
+// TestDiscoverProviderModels_FallsBackToTheStoredUrl keeps the plain refresh
+// working: a request naming only the record still reaches the saved upstream.
+func TestDiscoverProviderModels_FallsBackToTheStoredUrl(t *testing.T) {
+	ctx := context.Background()
+	f := newBootstrapFixture(t)
+	f.expectPermission("account1", "user1", modules.AgentNetworkProviders, operations.Create, true)
+	f.expectPermission("account1", "user1", modules.AgentNetworkProviders, operations.Create, true)
+
+	created, err := f.manager.CreateProvider(ctx, "user1", newCheckedProvider("account1"))
+	require.NoError(t, err)
+	stored := f.vendor.only(t).UpstreamURL
+	f.vendor.requests = nil
+
+	_, err = f.manager.DiscoverProviderModels(ctx, "account1", "user1", modeldiscovery.Request{
+		CatalogID: "openai_api",
+	}, created.ID)
+	require.NoError(t, err)
+
+	require.Equal(t, stored, f.vendor.only(t).UpstreamURL)
+}