Enable Intel iGPU hardware transcode by default for jellyfin-ha

The pod already requests gpu.intel.com/i915 and joins the render/video
groups, but Jellyfin transcodes in software until hardware acceleration
is turned on in its encoding config, which the fork does not template.

Seed /config/config/encoding.xml from the init container so VAAPI on the
injected Intel render node (/dev/dri/renderD128) is active on first boot:
HardwareAccelerationType vaapi, EnableHardwareEncoding, h264/hevc decode,
tonemapping left off. Rename the init container to inject-config and write
each seed file only when absent, so admin changes persisted to the shared
RWX /config are never clobbered on restart.

apps/base/jellyfin/statefulset.yaml

@@ -44,10 +44,12 @@ spec:
                     app: jellyfin
                 topologyKey: kubernetes.io/hostname
       initContainers:
-        # Select the fork's experimental PostgreSQL provider by writing
-        # database.xml before Jellyfin starts. Runs as root to chown into the
-        # shared config volume; mirrors the fork Helm chart's inject-db-config.
-        - name: inject-db-config
+        # Seed the fork's PostgreSQL provider (database.xml) and Intel iGPU
+        # hardware transcode settings (encoding.xml) before Jellyfin starts.
+        # Runs as root to chown into the shared config volume; mirrors the fork
+        # Helm chart's inject-db-config. Each file is written only when absent so
+        # admin changes persisted to the shared RWX /config survive pod restarts.
+        - name: inject-config
           image: busybox:1.37.0
           command:
             - sh
@@ -56,15 +58,47 @@ spec:
               mkdir -p /config/config
               chown 1000:1000 /config/config
               chmod 775 /config/config
-              cat > /config/config/database.xml << 'DBEOF'
+              if [ ! -e /config/config/database.xml ]; then
+                cat > /config/config/database.xml << 'DBEOF'
               <?xml version="1.0" encoding="utf-8"?>
               <DatabaseConfigurationOptions>
                 <DatabaseType>Jellyfin-PostgreSQL</DatabaseType>
                 <LockingBehavior>NoLock</LockingBehavior>
               </DatabaseConfigurationOptions>
               DBEOF
-              chown 1000:1000 /config/config/database.xml
-              chmod 664 /config/config/database.xml
+                chown 1000:1000 /config/config/database.xml
+                chmod 664 /config/config/database.xml
+              fi
+              # VAAPI on the Intel render node the device plugin injects
+              # (/dev/dri/renderD128 — ffmpeg's default DRM node, reachable via
+              # the render/video supplementalGroups). Without this the attached
+              # iGPU is idle and every transcode runs in software. Omitted
+              # elements fall back to the fork's EncodingOptions defaults.
+              if [ ! -e /config/config/encoding.xml ]; then
+                cat > /config/config/encoding.xml << 'ENCEOF'
+              <?xml version="1.0" encoding="utf-8"?>
+              <EncodingOptions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
+                <EncodingThreadCount>-1</EncodingThreadCount>
+                <HardwareAccelerationType>vaapi</HardwareAccelerationType>
+                <VaapiDevice>/dev/dri/renderD128</VaapiDevice>
+                <EnableHardwareEncoding>true</EnableHardwareEncoding>
+                <AllowHevcEncoding>true</AllowHevcEncoding>
+                <AllowAv1Encoding>false</AllowAv1Encoding>
+                <EnableIntelLowPowerH264HwEncoder>false</EnableIntelLowPowerH264HwEncoder>
+                <EnableIntelLowPowerHevcHwEncoder>false</EnableIntelLowPowerHevcHwEncoder>
+                <EnableTonemapping>false</EnableTonemapping>
+                <EnableVppTonemapping>false</EnableVppTonemapping>
+                <HardwareDecodingCodecs>
+                  <string>h264</string>
+                  <string>hevc</string>
+                  <string>vc1</string>
+                  <string>vp9</string>
+                </HardwareDecodingCodecs>
+              </EncodingOptions>
+              ENCEOF
+                chown 1000:1000 /config/config/encoding.xml
+                chmod 664 /config/config/encoding.xml
+              fi
           resources:
             requests:
               cpu: 10m
@@ -156,8 +190,9 @@ spec:
               memory: 6Gi
               # Intel iGPU (QSV/VA-API) slot. Requesting it pins the pod to a
               # GPU-labelled node and injects /dev/dri/renderD* automatically, so
-              # no /dev/dri hostPath or privileged container is needed. Enable
-              # QSV/VA-API once in the Jellyfin admin UI; it persists to /config.
+              # no /dev/dri hostPath or privileged container is needed. VA-API is
+              # pre-enabled via the seeded encoding.xml (see inject-config), so
+              # transcodes use the iGPU on first boot with no manual UI step.
               gpu.intel.com/i915: "1"
           securityContext:
             runAsUser: 1000