List workspaces with optional filtering.

Filters:

• role: "owner" (created by), "member" (invited to), or omit for all
• folder_id: Filter by folder
• include_progress: Include progress calculation (default: true)

Legacy filters:

• owner_id: Filter by owner (deprecated, use role=owner instead)

Returns lightweight card data for efficient list rendering. Stats (total_contents, etc.) are calculated dynamically from the database.

Examples:

• No params → All workspaces the authenticated user has access to
• ?role=owner → Workspaces created by the authenticated user
• ?role=member → Workspaces the authenticated user was invited to
• ?include_progress=false → Skip progress calculation for performance