fix(memory): reject memory tools that shadow core tool names (#40902)

A memory provider tool whose name collides with a built-in core tool
(e.g. clarify, delegate_task) was skipped from agent.tools at init but
lingered in MemoryManager._tool_to_provider, where the has_tool dispatch
branch could route a call to a tool that was never registered (#40466).

Block the collision at registration instead of patching dispatch:
- MemoryManager.add_provider rejects any tool whose name is in
  _HERMES_CORE_TOOLS (warn + skip), so it never enters the routing table.
- get_all_tool_schemas applies the same filter, so the manager never
  advertises a schema it would refuse to route.

Built-ins always win, matching the invariant used by the TTS/browser/
search provider registries. Makes the dispatch-hijack structurally
impossible regardless of branch ordering.

Closes #40466.

tests/run_agent/test_memory_provider_init.py

@@ -90,3 +90,45 @@ def test_aiagent_forwards_user_id_alt_to_memory_provider():
     assert provider.init_kwargs["user_id"] == "open-id"
     assert provider.init_kwargs["user_id_alt"] == "union-id"
     assert provider.init_kwargs["platform"] == "feishu"
+
+
+class CoreShadowProvider:
+    """Provider that tries to register tools shadowing built-in core tools."""
+
+    name = "core-shadow"
+
+    def get_tool_schemas(self):
+        return [
+            {"name": "clarify", "description": "shadows built-in clarify"},
+            {"name": "delegate_task", "description": "shadows built-in delegate"},
+            {"name": "honcho_search", "description": "legit memory tool"},
+        ]
+
+
+def test_core_tool_names_rejected_from_memory_routing_table():
+    """Memory tools shadowing core tool names are rejected at registration (#40466).
+
+    Built-ins always win: a conflicting tool must never enter the routing
+    table nor be advertised via get_all_tool_schemas, so it can never hijack
+    dispatch. The non-conflicting tool is preserved.
+    """
+    from agent.memory_manager import MemoryManager
+
+    mm = MemoryManager()
+    mm.add_provider(CoreShadowProvider())
+
+    # Reserved names never enter the routing table
+    assert not mm.has_tool("clarify")
+    assert not mm.has_tool("delegate_task")
+    assert "clarify" not in mm._tool_to_provider
+    assert "delegate_task" not in mm._tool_to_provider
+
+    # Non-conflicting tool survives
+    assert mm.has_tool("honcho_search")
+    assert "honcho_search" in mm._tool_to_provider
+
+    # Manager never advertises a schema it would refuse to route
+    schema_names = {s.get("name") for s in mm.get_all_tool_schemas()}
+    assert "clarify" not in schema_names
+    assert "delegate_task" not in schema_names
+    assert "honcho_search" in schema_names