Reapply "don't require pulling stubs for cloud models" again (#14608)

* Revert "Revert "Reapply "don't require pulling stubs for cloud models"" (#14606)"

This reverts commit 39982a954e.

* fix test + do cloud lookup only when seeing cloud models

---------

Co-authored-by: ParthSareen <parth.sareen@ollama.com>

cmd/tui/tui.go

@@ -11,6 +11,7 @@ import (
 	"github.com/charmbracelet/lipgloss"
 	"github.com/ollama/ollama/api"
 	"github.com/ollama/ollama/cmd/config"
+	"github.com/ollama/ollama/internal/modelref"
 	"github.com/ollama/ollama/version"
 )
 
@@ -147,7 +148,13 @@ type signInCheckMsg struct {
 type clearStatusMsg struct{}
 
 func (m *model) modelExists(name string) bool {
-	if m.availableModels == nil || name == "" {
+	if name == "" {
+		return false
+	}
+	if modelref.HasExplicitCloudSource(name) {
+		return true
+	}
+	if m.availableModels == nil {
 		return false
 	}
 	if m.availableModels[name] {
@@ -209,7 +216,7 @@ func (m *model) openMultiModelModal(integration string) {
 }
 
 func isCloudModel(name string) bool {
-	return strings.HasSuffix(name, ":cloud") || strings.HasSuffix(name, "-cloud")
+	return modelref.HasExplicitCloudSource(name)
 }
 
 func cloudStatusDisabled(client *api.Client) bool {