Bump version to 9.4.3 and introduce permission checks and UI/UX improvements. Changes include:

- pom.xml: version bumped to 9.4.3
- ItemActionHandler: check guishop.shop.<shop> and guishop.shop.* permissions (with OP bypass) and send no-permission message.
- Menu & Shop: unify how player-balance display name and lore are selected (prefer 'name' then 'shop-name'; 'lore' then 'shop-lore'), build a proper player head with owning player, set PDC keys for GUI elements and add editor mode hints.
- Shop: add refreshDynamicPrices() to efficiently update dynamic pricing lore/itemstacks without rebuilding the whole GUI, and openAtPage(player, page) helper to open to a specific page.
- Quantity & TransactionGui: remember the page the player opened from (returnPage) and, when returning/backing out, refresh dynamic prices and open the shop at the original page instead of a full reload.
- Fixed PLAYER_BALANCE items not correctly reading the lore or name from configs