core/cli: skip blocking GET /models on chat ready

Only fetch remote catalog when interactive model pick needs it; otherwise
use config/--model/session and warm Tab cache in the background. Cap list
fetch at 5s so a dead API cannot hang startup.

tests/test_cli/test_models_source.py

@@ -8,6 +8,7 @@ from plyngent.cli.models_source import (
     fetch_remote_model_ids,
     merge_model_choices,
     model_choices_for_provider,
+    needs_remote_models_for_selection,
 )
 from plyngent.config.models import ModelConfig, OpenAICompatibleProvider
 
@@ -55,3 +56,39 @@ async def test_fetch_remote_model_ids() -> None:
 
     with pytest.raises(TypeError, match="does not support"):
         _ = await fetch_remote_model_ids(object())
+
+
+@pytest.mark.asyncio
+async def test_fetch_remote_model_ids_timeout() -> None:
+    import asyncio
+
+    class Slow:
+        async def models(self) -> list[str]:
+            await asyncio.sleep(10)
+            return ["late"]
+
+    with pytest.raises(TimeoutError):
+        _ = await fetch_remote_model_ids(Slow(), timeout_seconds=0.05)
+
+
+def test_needs_remote_models_for_selection() -> None:
+    multi = OpenAICompatibleProvider(
+        access_key_or_token="sk",
+        url="https://x/v1",
+        models={"a": ModelConfig(), "b": ModelConfig()},
+    )
+    single = OpenAICompatibleProvider(
+        access_key_or_token="sk",
+        url="https://x/v1",
+        models={"only": ModelConfig()},
+    )
+    empty = OpenAICompatibleProvider(
+        access_key_or_token="sk",
+        url="https://x/v1",
+        models={},
+    )
+    assert needs_remote_models_for_selection(multi, preferred_model="a", interactive=True) is False
+    assert needs_remote_models_for_selection(multi, preferred_model=None, interactive=False) is False
+    assert needs_remote_models_for_selection(single, preferred_model=None, interactive=True) is False
+    assert needs_remote_models_for_selection(multi, preferred_model=None, interactive=True) is True
+    assert needs_remote_models_for_selection(empty, preferred_model=None, interactive=True) is True