Add Cinemachine third-person orbit camera and fix paint raycast

- Install Cinemachine 3.1.7 and set up an orbital third-person camera rig
  (CinemachineBrain, OrbitalFollow, RotationComposer, Deoccluder).
- Add ThirdPersonOrbitInput: mouse-driven orbit and wheel zoom with a Tab
  toggle that unlocks the cursor and pauses rotation.
- Fix MeshPainter so the paint ray skips the player's CharacterController
  capsule (and any other collider) and always targets the mesh collider,
  so painting works from every camera angle.

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

Assets/Scripts/MeshPainter.cs

@@ -89,6 +89,7 @@ public class MeshPainter : MonoBehaviour
     private int[] _fillStamp;                // transient marker for padding texels per dilation call
     private int _dilateStamp;                // incremented per call -> padding from previous frames does not count as a source
     private readonly List<int> _dilateScratch = new List<int>(512);
+    private readonly RaycastHit[] _rayHits = new RaycastHit[32]; // buffer so other colliders (player capsule, etc.) cannot block painting
     private int _dx0, _dy0, _dx1, _dy1;      // dirty rectangle (CPU upload)
 
     // --- GPU backend ---
@@ -480,8 +481,27 @@ public class MeshPainter : MonoBehaviour
     private void PaintAtScreen(Vector2 screenPos)
     {
         Ray ray = paintCamera.ScreenPointToRay(screenPos);
-        if (!(Physics.Raycast(ray, out RaycastHit hit, 1000f) && hit.collider == _collider))
-            return;
+
+        // Collect all hits and pick the nearest one that belongs to the paint mesh.
+        // A plain Physics.Raycast returns only the closest collider, so anything in
+        // front of the mesh (the player's CharacterController capsule, future props,
+        // the camera-collision proxy) would block painting. Filtering by collider
+        // keeps painting working from every camera angle.
+        int hitCount = Physics.RaycastNonAlloc(ray, _rayHits, 1000f, ~0, QueryTriggerInteraction.Ignore);
+        RaycastHit hit = default;
+        float nearest = float.MaxValue;
+        bool found = false;
+        for (int i = 0; i < hitCount; i++)
+        {
+            if (_rayHits[i].collider != _collider) continue;
+            if (_rayHits[i].distance < nearest)
+            {
+                nearest = _rayHits[i].distance;
+                hit = _rayHits[i];
+                found = true;
+            }
+        }
+        if (!found) return;
         if (_verts == null || hit.triangleIndex < 0) return;
 
         // Bring the hit point into local mesh space (= collider/vertex space).