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>

src/mcp_synology_filestation/tools/filestation.py

@@ -358,7 +358,7 @@ def register_filestation(
                 "SYNO.FileStation.Search",
                 "start",
                 params={
-                    "folder_path": path,
+                    "folder_path": json.dumps([path]),
                     "recursive": "true" if recursive else "false",
                     "pattern": pattern,
                 },
@@ -845,7 +845,7 @@ def register_filestation(
                 "start",
                 version=2,
                 params={
-                    "file_path": json.dumps(file_path),
+                    "path": json.dumps(file_path),
                     "dest_folder_path": json.dumps(dest_folder_path),
                     "overwrite": "true" if overwrite else "false",
                     "keep_dir": "true" if keep_dir else "false",