fix(llm): make logout-all atomic and persist provider in run record

Second review pass:
- strix auth logout (all providers) now holds the shared store lock across every provider removal, so a concurrent save/refresh cannot leave one credential behind while reporting all removed.
- _persist_run_record writes subscription_provider alongside auth_mode, matching ReportState, so resumed runs keep their original provider label.

tests/test_auth_cli.py

@@ -95,6 +95,31 @@ def test_model_subcommand_removed() -> None:
     assert auth_cli.run_auth(["model", "gpt-5.5"]) == 2
 
 
+def _sign_in_both() -> None:
+    codex.save_record({"type": "oauth", "access": "c", "refresh": "r", "account_id": "a"})
+    grok.save_record({"type": "oauth", "access": "g", "refresh": "r"})
+
+
+def test_logout_all_removes_every_provider() -> None:
+    _sign_in_both()
+    assert codex.is_authenticated()
+    assert grok.is_authenticated()
+
+    assert auth_cli.run_auth(["logout"]) == 0
+
+    assert not codex.is_authenticated()
+    assert not grok.is_authenticated()
+
+
+def test_logout_single_provider_leaves_the_other() -> None:
+    _sign_in_both()
+
+    assert auth_cli.run_auth(["logout", "grok"]) == 0
+
+    assert codex.is_authenticated()
+    assert not grok.is_authenticated()
+
+
 @pytest.mark.parametrize("provider", ["chatgpt", "codex", "ChatGPT"])
 def test_login_accepts_provider_aliases(provider: str, monkeypatch: pytest.MonkeyPatch) -> None:
     reached = {"flow": False}