fix: accept integrated GPUs in physical device selection

[DasPauluteli]

Problem

findPhysicalDevice() in src/core/vulkan/physical_device.cpp has a hard-coded filter that rejects any device that is not VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU:

if (properties.deviceType != VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU) continue;

This silently discards APUs and integrated GPUs that fully satisfy every actual capability requirement, causing an immediate crash on startup:

[PhysicalDevice] No suitable physical device found!

This affects at least:

• No suitable device found on amd gpu even though rayTracingPipeline is supported Radiance#214 – AMD Custom GPU 0405 (RADV VANGOGH APU) — rayTracingPipeline = true, still rejected
• Crash when lunch on AMD Radeon 880M with Adrenalin Edition 26.3.1 Radiance#240 – AMD Radeon 880M (Hawk Point APU, Windows)
• Silent crash on startup with Radiance 0.1.2-preview on Intel Arc 140T Radiance#87 – Intel Arc 140T (reports as INTEGRATED_GPU)

Fix

Remove the device-type filter. isDeviceSuitable() already checks every capability that actually matters:

• VK_KHR_swapchain ✓
• VK_KHR_ray_tracing_pipeline ✓
• accelerationStructure ✓
• synchronization2 ✓
• bufferDeviceAddress ✓

Selection is now purely capability-based.

Tested on

Field	Value
GPU	AMD Radeon 8060S Graphics (RADV STRIX_HALO)
GPU type	VK_PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU
Vulkan API	1.4.348
Driver	RADV 26.1.0
Vendor	AMD (0x1002)
OS	CachyOS (Arch-based), KDE Plasma 6 / Wayland
CPU	AMD Ryzen AI Max+ 395 (RDNA4 APU, gfx1151, STRIX_HALO)
Radiance	0.1.5-alpha, Fabric 1.21.4

All RT extensions confirmed present: VK_KHR_acceleration_structure, VK_KHR_ray_tracing_pipeline, VK_KHR_ray_query.

Diff

-            if (properties.deviceType != VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU) continue;
-
             physicalDevice_ = device;

[Interstellarss]

I think there is a selection mechanism in the dev branch for version 0.1.3-alpha, but at the time it is not really working on a intel integrated GPU that has ray tracing unit. If it is working on a amd integrated gpu, could you also share the performance on this device?