Pie menu, weapon system, Btn node, weapon slots wired to player
- Replace RadialMenu with PieMenu: 12-segment pie with visibility bits
- Add pie-menu-uifs.sc with per-segment visibility and hover highlight
- Add Btn node with hover highlight shader and onClick callback
- Add close button to InvUi via Btn node
- Add Weapon::Ctor with mesh, idle, attack, and player attack anims
- Wire Staff and Bhs constructors to Weapon::Ctor with anim paths
- Add Player::setCurWeapon: spawns weapon SkMesh from Weapon item data
- Add Player::onPieMenuSelected: routes pie selection to weapon/inv/etc
- Player::secondaryTrig opens pie menu and centers/hides cursor
- Pie menu closing restores cursor and HUD visibility
- Remove hardcoded BHS anim refs from Player; use curWeapon instead
- Weapon slot null-guard: only attack if curWeapon and weapon exist
- Add typed Slot::getItem() returning const I*
- Add BaseSlot::getItem() returning const Item*
- Add InvUi weapon slot getters for pie menu visibility checks
- Add isVisible guard to mouseBtnDown/Up/Wheel in NodeUi
- Fix TileView left click to return onTileClick result
- Remove unused hp-ico and mana-ico from asset preloads
- Remove log statements from loot, crystal sanctuary guardian
- Assert on texture load failure instead of logging