fix: add video driver capability so NVENC works in the container

The Go-Live broadcast encodes with h264_nvenc, but the image only requested
NVIDIA_DRIVER_CAPABILITIES=compute,utility. The NVIDIA Container Toolkit gates
which driver libraries it injects by capability, and the NVENC/NVDEC libs
(libnvidia-encode.so.1 / libnvidia-decode.so.1) come with the `video`
capability. Without it the broadcast ffmpeg dies with
"Cannot load libnvidia-encode.so.1", the capture produces no packets, and
Go-Live never connects, while CUDA workloads (ollama/whisper/melo) and
nvidia-smi keep working because compute+utility are present.

Add `video` so hardware encode is available. Applies to both Linux (CDI) and
Windows Docker Desktop (WSL2).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Dockerfile

@@ -10,8 +10,14 @@ ENV DEBIAN_FRONTEND=noninteractive \
     DISPLAY=:1 \
     PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 \
     PATH=/opt/venv/bin:/root/.bun/bin:/usr/local/bin:/usr/bin:/bin \
-    NVIDIA_VISIBLE_DEVICES=all \
-    NVIDIA_DRIVER_CAPABILITIES=compute,utility
+    NVIDIA_VISIBLE_DEVICES=all
+
+# `video` is REQUIRED for NVENC/NVDEC: it tells the NVIDIA Container Toolkit to
+# inject libnvidia-encode.so.1 / libnvidia-decode.so.1 into the container. With
+# only `compute,utility` you get CUDA (ollama/whisper/melo) + nvidia-smi, but the
+# Go-Live broadcast's h264_nvenc fails with "Cannot load libnvidia-encode.so.1".
+# Applies on both Linux (CDI) and Windows Docker Desktop (WSL2).
+ENV NVIDIA_DRIVER_CAPABILITIES=compute,utility,video
 
 # --- System packages: desktop, VNC, Chrome deps, ffmpeg, python, ocr ---
 RUN apt-get update && apt-get install -y --no-install-recommends \