Wall-climb mesh lean + separate climb/mantle/sprint speeds; reworked rig

PlayerCharacterController:
- Wall lean now moves only the visual model + its paint collider (auto-resolved
  mesh root parenting both renderer and bones), not the CharacterController
  capsule, so the mesh can sink into the wall (wallMaxInset) as well as lean out
  (wallMaxOffset); capsule stays flush.
- Lean eases back to the authored pose when leaving the wall instead of snapping.
- Sprint multiplier now also applies while wall/ceiling climbing.
- Separate wallMantleSpeedMultiplier for pulling up over the top edge,
  independent of the climb speed.

Assets:
- Re-exported paintman_UV.FBX and added Paintman.blend: rescaled armature to
  mesh, merged seam duplicate vertices, fresh automatic weights, inner-thigh
  weight fix (no webbing on leg spread).
- Updated anims, animator controller, font SDF and scene.

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

Assets/Models/Paintman.controller

@@ -88,10 +88,10 @@ AnimatorStateMachine:
   m_ChildStates:
   - serializedVersion: 1
     m_State: {fileID: -6714276574684263144}
-    m_Position: {x: 280, y: -10, z: 0}
+    m_Position: {x: 330, y: 10, z: 0}
   - serializedVersion: 1
     m_State: {fileID: -6819265730547739275}
-    m_Position: {x: 260, y: 60, z: 0}
+    m_Position: {x: 320, y: 100, z: 0}
   - serializedVersion: 1
     m_State: {fileID: -1498405215906516480}
     m_Position: {x: 150, y: -110, z: 0}
@@ -111,7 +111,7 @@ AnimatorStateMachine:
   m_EntryPosition: {x: 50, y: 120, z: 0}
   m_ExitPosition: {x: 570, y: -10, z: 0}
   m_ParentStateMachinePosition: {x: 800, y: 20, z: 0}
-  m_DefaultState: {fileID: -6819265730547739275}
+  m_DefaultState: {fileID: -6714276574684263144}
 --- !u!1102 &-2107490064458262391
 AnimatorState:
   serializedVersion: 6