fix(agent): add regression test for #65429 (memory store with skip_memory + memory toolset)

Behavioral test constructing a real AIAgent with skip_memory=True and
enabled_toolsets=["memory"] asserts the built-in MemoryStore is created
(store is not None). Also covers the negative case (no memory toolset -> None)
and the normal case (skip_memory=False -> store created).

tests/agent/test_skip_memory_store_65429.py

@@ -0,0 +1,65 @@
+"""Regression test for issue #65429.
+
+An agent built with ``skip_memory=True`` AND ``enabled_toolsets=["memory"]``
+used to get a memory tool wired to ``store=None`` (the built-in
+``MemoryStore`` was skipped along with the external provider), so every
+memory call failed silently and the main auto-capture path was dead.
+
+The fix creates the built-in store whenever memory is enabled in config OR the
+memory toolset is explicitly enabled, while the external-provider block stays
+gated on ``skip_memory``.
+"""
+
+import pytest
+
+from run_agent import AIAgent
+
+
+class _FakeOpenAI:
+    def __init__(self, **kw):
+        self.api_key = kw.get("api_key", "test")
+        self.base_url = kw.get("base_url", "http://test")
+
+    def close(self):
+        pass
+
+
+def _make_agent(monkeypatch, enabled_toolsets=None, skip_memory=True):
+    monkeypatch.setattr("run_agent.get_tool_definitions", lambda **kw: [])
+    monkeypatch.setattr("run_agent.check_toolset_requirements", lambda: {})
+    monkeypatch.setattr("run_agent.OpenAI", _FakeOpenAI)
+    return AIAgent(
+        api_key="test-key",
+        base_url="http://test",
+        provider="openrouter",
+        api_mode="chat_completions",
+        max_iterations=1,
+        quiet_mode=True,
+        skip_context_files=True,
+        skip_memory=skip_memory,
+        enabled_toolsets=enabled_toolsets,
+    )
+
+
+def test_skip_memory_with_memory_toolset_creates_store(monkeypatch, tmp_path):
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hm"))
+    agent = _make_agent(monkeypatch, enabled_toolsets=["memory"], skip_memory=True)
+    assert agent._memory_store is not None, (
+        "memory toolset enabled despite skip_memory=True must still build "
+        "the built-in store (#65429)"
+    )
+
+
+def test_skip_memory_without_memory_toolset_has_no_store(monkeypatch, tmp_path):
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hm"))
+    agent = _make_agent(monkeypatch, enabled_toolsets=None, skip_memory=True)
+    assert agent._memory_store is None, (
+        "flush/background agent with skip_memory and no memory toolset must "
+        "have no built-in store"
+    )
+
+
+def test_memory_toolset_without_skip_memory_creates_store(monkeypatch, tmp_path):
+    monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hm"))
+    agent = _make_agent(monkeypatch, enabled_toolsets=["memory"], skip_memory=False)
+    assert agent._memory_store is not None