Port gmPanelUI's persistent parent placement semantics across Inventory, Character, and Magic while preserving each imported child's content and resize policy. Synchronize typed retained-window handles so drag, switching, close/reopen, and layout persistence all observe one canonical location; keep effect panels independent.
User-verified in normal Release. Release build and all 5,770 tests passed with five intentional skips.
Co-authored-by: OpenAI Codex <codex@openai.com>
