Drop fabricated "example" models for codex/gemini

The codex/gemini model listers returned hardcoded "example" model ids
that looked pickable but weren't guaranteed valid (gpt-5-codex could fail
outright). Neither CLI has a model-enumeration command, so remove the
listers entirely. The model picker then offers just Default + Custom for
those agents (its existing no-models behavior), and `--models` shows
"(no advertised models; pass any value your CLI accepts via --model)".

Claude keeps its real, valid aliases (opus/sonnet/haiku). Tests updated.

Entire-Checkpoint: ebcc924da0df

Author: dipree

cmd/entire/cli/agent/codex/models.go

@@ -136,11 +136,16 @@ func TestReviewCmd_ListModels(t *testing.T) {
 		t.Fatalf("execute: %v", err)
 	}
 	out := buf.String()
-	for _, want := range []string{"claude-code", "opus", "sonnet", "codex", "gpt-5-codex", "gemini", "gemini-2.5-pro"} {
+	// claude-code advertises real aliases; codex/gemini have no enumeration
+	// command, so they list no models and point at Default/--model instead.
+	for _, want := range []string{"claude-code", "opus", "sonnet", "codex", "gemini", "no advertised models"} {
 		if !strings.Contains(out, want) {
 			t.Errorf("--models output missing %q:\n%s", want, out)
 		}
 	}
+	if strings.Contains(out, "gpt-5-codex") {
+		t.Errorf("--models should not invent example codex models:\n%s", out)
+	}
 }
 
 // TestReviewCmd_ListModelsFilteredByAgent verifies the --agent filter narrows
@@ -155,11 +160,11 @@ func TestReviewCmd_ListModelsFilteredByAgent(t *testing.T) {
 		t.Fatalf("execute: %v", err)
 	}
 	out := buf.String()
-	if !strings.Contains(out, "gpt-5-codex") {
-		t.Errorf("expected codex models, got:\n%s", out)
+	if !strings.Contains(out, "codex") || !strings.Contains(out, "no advertised models") {
+		t.Errorf("expected codex section with no-advertised-models note, got:\n%s", out)
 	}
-	if strings.Contains(out, "gemini-2.5-pro") {
-		t.Errorf("--agent codex should not list gemini models:\n%s", out)
+	if strings.Contains(out, "gemini") {
+		t.Errorf("--agent codex should not list gemini:\n%s", out)
 	}
 }