Replace auto paint persistence with a named painting library

Persistence rework:
- Drop auto-load on setup and auto-save on teardown; the painter now always
  seeds fresh from the material.
- Named slots under MeshPaint/Saved/<name>.paint via the existing CHMP
  machinery: SavePaintAs / LoadPaintByName / DeletePaint / ListSavedPaintings /
  PaintExists. Slot files carry the display name in the header.
- Remove the obsolete persistence partials (PlayerCharacterController,
  PlayerPoseController, ThirdPersonOrbitInput) and their references.

Paintings HUD panel:
- Authored Panel_Paintings + Save/Load/Delete dialogs into PaintHudPanel.prefab
  (TMP throughout); PaintHud.Library.cs is now a pure binder that clones the
  entry template per slot.
- Save dialog blocks empty/existing names; Load and Delete confirm first.
- Fix dialog z-order: open dialogs SetAsLastSibling so a dragged panel can no
  longer cover them.
- Lib_ListContent horizontal offsets corrected to 0 (was clipping entry labels
  out of the masked viewport).

Multiplayer:
- Loading a painting re-syncs to all peers via the snapshot broadcast path
  (BroadcastLoadedPaint), covering later late-joiners for free.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/Scripts/PlayerPoseController.cs

@@ -34,7 +34,7 @@ using UnityEngine.InputSystem;
 // Run after PlayerCharacterController (default order 0) so the sprint / locomotion state polled below is
 // this frame's, and the per-pose capsule / camera offset resolve without a one-frame seam.
 [DefaultExecutionOrder(100)]
-public partial class PlayerPoseController : MonoBehaviour
+public class PlayerPoseController : MonoBehaviour
 {
     [Header("Poses")]
     [Tooltip("Selectable poses. Index 0 is the default pose that sprinting resets to.")]