fix(registry): normalize path case for comparison on Windows

Adds case normalization for path comparison on Windows to handle
case-insensitive filesystem behavior. Preserves case-sensitivity on Unix.

Fixes: ISS-1766921318981-13

Solution-ID: SOL-1735386000-13
Issue-ID: ISS-1766921318981-13
Task-ID: T1

codex-lens/tests/test_registry.py

@@ -0,0 +1,69 @@
+"""Tests for RegistryStore path handling."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from codexlens.storage.registry import RegistryStore
+
+
+def _swap_case(path: Path) -> str:
+    return str(path).swapcase()
+
+
+def test_path_case_normalization_windows(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    """On Windows, path comparisons should be case-insensitive."""
+    import codexlens.storage.registry as registry
+
+    monkeypatch.setattr(registry.platform, "system", lambda: "Windows")
+
+    db_path = tmp_path / "registry.db"
+    source_root = tmp_path / "MyProject"
+    index_root = tmp_path / "indexes"
+
+    with RegistryStore(db_path=db_path) as store:
+        store.register_project(source_root, index_root)
+
+        result = store.find_by_source_path(_swap_case(source_root))
+        assert result is not None
+        assert result["source_root"] == str(source_root.resolve()).lower()
+
+
+def test_path_case_sensitivity_non_windows(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    """On Unix, path comparisons should remain case-sensitive."""
+    import codexlens.storage.registry as registry
+
+    monkeypatch.setattr(registry.platform, "system", lambda: "Linux")
+
+    db_path = tmp_path / "registry.db"
+    source_root = tmp_path / "MyProject"
+    index_root = tmp_path / "indexes"
+
+    with RegistryStore(db_path=db_path) as store:
+        store.register_project(source_root, index_root)
+        assert store.find_by_source_path(_swap_case(source_root)) is None
+
+
+def test_find_nearest_index(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    """Nearest ancestor lookup should be case-insensitive on Windows."""
+    import codexlens.storage.registry as registry
+
+    monkeypatch.setattr(registry.platform, "system", lambda: "Windows")
+
+    db_path = tmp_path / "registry.db"
+    source_root = tmp_path / "MyProject"
+    index_root = tmp_path / "indexes"
+    index_db = index_root / "_index.db"
+
+    with RegistryStore(db_path=db_path) as store:
+        project = store.register_project(source_root, index_root)
+        mapping = store.register_dir(project.id, source_root, index_db, depth=0)
+
+        query_path = Path(_swap_case(source_root)) / "SubDir" / "file.py"
+        found = store.find_nearest_index(query_path)
+
+        assert found is not None
+        assert found.id == mapping.id
+