[Bug]: HDR + fullscreen video causes GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT and session crash on Blackwell (RTX 5070 Ti) with driver 595.x

### Kernel

7.0.1-1-cachyos

### Desktop Environment / Window Manager

KDE Plasma

### CPU

AMD Ryzen 7 9800X3D (8) @ 5.27 GHz

### GPU / Driver

NVIDIA GeForce RTX 5070 Ti (Blackwell)

### Description

SUMMARY
KDE Plasma 6.6.4 Wayland session crashes when HDR is enabled and fullscreen
video is played. Disabling HDR completely resolves the issue.

STEPS TO REPRODUCE
1. Enable HDR in System Settings → Display and Monitor
2. Play any fullscreen 4K video with mpv on Wayland
3. KWin crashes within minutes

OBSERVED RESULT
kwin_wayland: Invalid framebuffer status: "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT"
kwin_wayland: atomic commit failed: Permission denied
kwin_wayland: Failed to open drm device /dev/dri/card0
Session crashes, all applications killed.

EXPECTED RESULT
HDR playback should work without crashing the compositor.

SOFTWARE/OS VERSIONS
Operating System: CachyOS (Arch-based)
KDE Plasma Version: 6.6.4
Kernel Version: 7.0.1-1-cachyos
Graphics Platform: Wayland
GPU: NVIDIA GeForce RTX 5070 Ti (Blackwell)
Driver: 595.71.05

ADDITIONAL INFORMATION
This is related to bug #491751 which was marked resolved but is NOT fixed
for Blackwell GPUs on driver 595.x. Workaround is disabling HDR entirely.

### Steps to Reproduce

1. Enable HDR in System Settings → Display and Monitor → Enable HDR checkbox
2. Open any 4K HDR video in mpv fullscreen on Wayland
3. Within minutes KWin crashes and kills the entire Wayland session

### Expected Behavior

HDR should work alongside fullscreen video playback without crashing the compositor.

### Actual Behavior

KWin crashes with GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT, atomic commit fails,
DRM access is revoked, entire session dies. All running applications are killed.
Workaround: disabling HDR in Display Settings completely stops the crashes.

### Logs / Error Messages

kwin_wayland: GL_INVALID_VALUE error generated. , and must be 1 or greater. kwin_wayland: Invalid framebuffer status: "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT" kwin_wayland: Failed to create an offscreen framebuffer kwin_wayland: atomic commit failed: Permission denied kwin_wayland: Failed to open drm device /dev/dri/card0 kwin_wayland: Atomic modeset test failed! Permission denied kwin_wayland: Applying output configuration failed!

### Additional Context

GPU: RTX 5070 Ti (Blackwell) — Driver: 595.71.05
Plasma: 6.6.4 — Kernel: 7.0.1-1-cachyos — Wayland

Related: KDE bug #491751 (marked resolved but not fixed for Blackwell)
Also reported on nvidia developer forums.
Root cause confirmed by KDE developer Zamundaaa: nvidia driver bug in
HDR output configuration path.