Two fixes from the systematic stub audit:
1. Mesa recipe: add hardware GPU drivers for Intel and AMD parity.
- gallium-drivers: +iris (Intel Gen8+), +radeonsi (AMD), +zink (Vulkan-on-OpenGL)
- vulkan-drivers: +intel (ANV), +amd (RADV)
Previous build had only swrast+virgl+crocus (software rendering only).
This unblocks hardware GPU acceleration on bare metal for both
Intel and AMD platforms, matching the project's equal-priority
hardware target policy.
2. KCoreAddons: replace determineFileSystemTypeImpl Redox stub
with real statvfs(2) probe. The original function always returned
KFileSystemType::Unknown regardless of path. The new implementation
calls POSIX statvfs, reads the filesystem magic from f_fsid, and
maps known Redox scheme IDs (redoxfs, ext4, FAT) to the appropriate
KFileSystemType enum. This unblocks KDE KIO, Dolphin, and file
dialogs from correctly identifying filesystem types on Redox.
Ported from Linux 7.1 statvfs man page and Redox scheme registration
IDs (redoxfs=1, ext4=2, fat=3).