Fixes#327
- Use absolute path (~/.workspace-mcp/attachments/) instead of relative
./tmp/attachments to avoid polluting working directories
- Make storage directory configurable via WORKSPACE_ATTACHMENT_DIR env var
- Return file path from save_attachment() instead of UUID for direct
filesystem access (useful in stdio mode where HTTP URLs are unavailable)
- Preserve original filenames with UUID suffix for uniqueness
- Use format="full" instead of format="metadata" when fetching attachment
info, as metadata format doesn't include attachmentId in parts
- Add multi-level filename matching: exact attachmentId → size-based
fallback → single-attachment fallback (handles ephemeral IDs)
57daf2ab30