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/__init__.py

@@ -1,3 +1,3 @@
 """MCP server for Synology FileStation."""
 
-__version__ = "0.3.1"
+__version__ = "0.3.2"