fix(filesystem): escape sqlite like wildcards

Escape wildcard characters in recursive folder LIKE filters and metadata contains queries.

tests/test_pifs_like_escape.py

@@ -0,0 +1,115 @@
+from pathlib import Path
+
+
+def _register_file(
+    filesystem,
+    tmp_path: Path,
+    filename: str,
+    *,
+    folder_path: str,
+    external_id: str,
+    metadata: dict[str, str] | None = None,
+) -> None:
+    source = tmp_path / filename
+    source.write_text(f"{external_id} fixture text", encoding="utf-8")
+    filesystem.register_file(
+        storage_uri=source.as_uri(),
+        source_path=f"docs/{filename}",
+        folder_path=folder_path,
+        external_id=external_id,
+        title=external_id,
+        content=source.read_text(encoding="utf-8"),
+        metadata=metadata or {},
+    )
+
+
+def test_descendant_folder_filter_treats_underscore_literally(tmp_path):
+    from pageindex.filesystem import PageIndexFileSystem
+
+    filesystem = PageIndexFileSystem(workspace=tmp_path / "workspace")
+    _register_file(
+        filesystem,
+        tmp_path,
+        "literal.txt",
+        folder_path="/proj_1/docs",
+        external_id="literal_underscore",
+    )
+    _register_file(
+        filesystem,
+        tmp_path,
+        "wildcard.txt",
+        folder_path="/projA1/docs",
+        external_id="wildcard_neighbor",
+    )
+
+    recursive = filesystem.browse("/proj_1", recursive=True, limit=10)
+    folder_id = filesystem.folder_info("/proj_1")["folder_id"]
+    scoped_results = filesystem.search(
+        scope={"folder_id": folder_id, "recursive": True},
+        semantic=False,
+        limit=10,
+    )
+    ranked_folders = {
+        folder["path"]: folder
+        for folder in filesystem.find_folders("/", max_depth=1, limit=10)
+    }
+
+    assert {folder["path"] for folder in recursive["folders"]} == {"/proj_1/docs"}
+    assert {file["external_id"] for file in recursive["files"]} == {"literal_underscore"}
+    assert {result.external_id for result in scoped_results} == {"literal_underscore"}
+    assert ranked_folders["/proj_1"]["matched_files"] == 1
+    assert ranked_folders["/projA1"]["matched_files"] == 1
+    assert filesystem.store.count_files_in_folder("/proj_1", recursive=True) == 1
+
+
+def test_metadata_contains_treats_percent_and_underscore_literally(tmp_path):
+    from pageindex.filesystem import PageIndexFileSystem
+
+    filesystem = PageIndexFileSystem(workspace=tmp_path / "workspace")
+    filesystem.metadata.register_schema({"fields": {"status": "string"}})
+    _register_file(
+        filesystem,
+        tmp_path,
+        "percent.txt",
+        folder_path="/documents",
+        external_id="literal_percent",
+        metadata={"status": "100% done"},
+    )
+    _register_file(
+        filesystem,
+        tmp_path,
+        "percent-neighbor.txt",
+        folder_path="/documents",
+        external_id="percent_neighbor",
+        metadata={"status": "100X done"},
+    )
+    _register_file(
+        filesystem,
+        tmp_path,
+        "underscore.txt",
+        folder_path="/documents",
+        external_id="literal_underscore",
+        metadata={"status": "build_alpha"},
+    )
+    _register_file(
+        filesystem,
+        tmp_path,
+        "underscore-neighbor.txt",
+        folder_path="/documents",
+        external_id="underscore_neighbor",
+        metadata={"status": "buildXalpha"},
+    )
+
+    percent_results = filesystem.search(
+        metadata_filter={"status": {"$contains": "100% done"}},
+        semantic=False,
+        limit=10,
+    )
+    underscore_results = filesystem.search(
+        metadata_filter={"status": {"$contains": "build_alpha"}},
+        semantic=False,
+        limit=10,
+    )
+
+    assert {result.external_id for result in percent_results} == {"literal_percent"}
+    assert {result.external_id for result in underscore_results} == {"literal_underscore"}