fix(rendering): wait all frame fences before freeing shared descriptor sets

deferAfterFrameFence only waits for one frame slot's fence, but shared
resources (material descriptor sets, vertex/index buffers) are bound by
both in-flight frames' command buffers. On AMD RADV this caused
vkFreeDescriptorSets errors and eventual SIGSEGV.

Add deferAfterAllFrameFences: queues to every frame slot with a shared
counter so cleanup runs exactly once, after the last slot is fenced.
Use it for WMO, terrain, water, and character model shared resources.
Per-frame bone sets keep using deferAfterFrameFence (already correct).

Also fix character renderer vertex format: R8G8B8A8_UINT -> _SINT to
match shader's ivec4 input (RADV validation rejects the mismatch).

src/rendering/wmo_renderer.cpp

@@ -1972,7 +1972,7 @@ void WMORenderer::destroyGroupGPU(GroupResources& group, bool defer) {
         }
 
         VkDescriptorPool pool = materialDescPool_;
-        vkCtx_->deferAfterFrameFence([device, allocator, pool, vb, vbAlloc, ib, ibAlloc,
+        vkCtx_->deferAfterAllFrameFences([device, allocator, pool, vb, vbAlloc, ib, ibAlloc,
                                       mats = std::move(mats)]() {
             if (vb) vmaDestroyBuffer(allocator, vb, vbAlloc);
             if (ib) vmaDestroyBuffer(allocator, ib, ibAlloc);