fix: search empty results + extract error 408 (v0.3.2)

Bug 1 — search always returned empty results:
  Search::start was passing folder_path as a plain string.
  DSM silently ignores a plain string for this parameter and returns
  finished=True with files=[] immediately, as if nothing was found.
  Fix: json.dumps([path]) — JSON array, matching the multi-path API
  pattern used by DirSize::start and List::getinfo.

Bug 2 — extract returned DSM error 408:
  Extract::start was using "file_path" as the parameter key for the
  source archive. DSM expects "path". Without a valid path DSM returned
  error 408. The json.dumps wrapping was already correct.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_tools_filestation.py

@@ -463,7 +463,7 @@ async def test_search_success(config: AppConfig) -> None:
     start_call = client.request.call_args_list[0]
     assert start_call[0][0] == "SYNO.FileStation.Search"
     assert start_call[0][1] == "start"
-    assert start_call[1]["params"]["folder_path"] == "/docker"
+    assert json.loads(start_call[1]["params"]["folder_path"]) == ["/docker"]
     assert start_call[1]["params"]["pattern"] == "*.yaml"
     assert start_call[1]["params"]["recursive"] == "true"
     # Verify clean was called last
@@ -1353,7 +1353,7 @@ async def test_extract_success(config: AppConfig) -> None:
     assert start_call[0][1] == "start"
     assert start_call[1]["version"] == 2
     p = start_call[1]["params"]
-    assert json.loads(p["file_path"]) == "/backup/archive.zip"
+    assert json.loads(p["path"]) == "/backup/archive.zip"
     assert json.loads(p["dest_folder_path"]) == "/data/extracted"
     assert p["overwrite"] == "false"
     assert p["keep_dir"] == "true"