Add benchmark results and tests for LSP graph builder and staged search

- Introduced a new benchmark results file for performance comparison on 2026-02-09.
- Added a test for LspGraphBuilder to ensure it does not expand nodes at maximum depth.
- Created a test for the staged search pipeline to validate fallback behavior when stage 1 returns empty results.

codex-lens/tests/test_lsp_graph_builder_depth.py

@@ -0,0 +1,36 @@
+from __future__ import annotations
+
+import asyncio
+from unittest.mock import AsyncMock
+
+import pytest
+
+from codexlens.hybrid_search.data_structures import CodeAssociationGraph, CodeSymbolNode, Range
+from codexlens.lsp.lsp_graph_builder import LspGraphBuilder
+
+
+@pytest.mark.asyncio
+async def test_lsp_graph_builder_does_not_expand_at_max_depth() -> None:
+    """Depth semantics: max_depth is the number of hops from seeds."""
+    builder = LspGraphBuilder(max_depth=1, max_nodes=10, max_concurrent=1, resolve_symbols=False)
+
+    bridge = AsyncMock()
+    bridge.get_references.side_effect = RuntimeError("should not call references")
+    bridge.get_call_hierarchy.side_effect = RuntimeError("should not call call hierarchy")
+
+    node = CodeSymbolNode(
+        id="x.py:foo:1",
+        name="foo",
+        kind="function",
+        file_path="x.py",
+        range=Range(start_line=1, start_character=1, end_line=1, end_character=1),
+    )
+    graph = CodeAssociationGraph()
+    visited: set[str] = set()
+    sem = asyncio.Semaphore(1)
+
+    # Seeds are depth=0. A node at depth==max_depth should not be expanded.
+    new_nodes = await builder._expand_node(node, 1, graph, bridge, visited, sem)  # type: ignore[attr-defined]
+    assert new_nodes == []
+    assert node.id in visited
+