feat(jellyfin): the provider keys ride a host file the deployer installs

Jellyfin 12 ships TMDB, TVDB, StudioImages and MusicBrainz as core plugins:
no DLL, only a configuration file under the data root, so the keys have to
reach that XML from somewhere that is not git. They live in the fleet's
per-service env-file convention -- /home/dank/Containers/jellyfin/provider-keys
(TMDB_API_KEY=, TVDB_API_KEY=, optional TVDB_PIN=, mode 600) -- and
scripts/jellyfin-providers.sh plan|install|verify reads only that file, prints
no key byte, and refuses a keys file that is not mode 600 or that has no line
for the provider about to be written. install is idempotent: it never touches
a key the UI already saved, backs up every XML it edits into
~/.AGENTTRASH/<date>-jellyfin-providers/ first, and only installs the TVDB
plugin when the pinned official zip carries the plugin guid.

The deployer runs install BEFORE it restarts jellyfin, because the plugin and
its keys are read at start-up and a restart-first deploy boots the old state.
A missing keys file warns instead of failing: a host without the keys still
deploys, degraded rather than broken. No plugin configuration XML is tracked.

scripts/deploy-remote.sh

@@ -1216,8 +1216,28 @@ ensure_media_view() {
     bash scripts/media-view.sh verify
 }
 
+ensure_provider_keys() {
+    # Jellyfin's metadata-provider keys live in the container-owned plugin
+    # configuration under the data root, never in git; scripts/jellyfin-providers.sh
+    # is what places them, reading the per-service host env file (the fleet
+    # convention: grafana, caddy, pihole, copyparty, romm, seerr) that holds
+    # TMDB_API_KEY= and TVDB_API_KEY=, mode 600.
+    # Missing keys mean a keyless provider — a degraded library, not a broken
+    # deploy — so this warns rather than failing the restart. But when the keys
+    # ARE placed it must happen before the restart: the plugin and its keys are
+    # read at start-up, so a restart first would boot the old state.
+    local keys=/home/dank/Containers/jellyfin/provider-keys
+    if [ -f "$keys" ]; then
+        bash scripts/jellyfin-providers.sh install
+    else
+        echo "WARN: $keys is absent - provider keys NOT placed"
+        echo "WARN: create it (TMDB_API_KEY=, TVDB_API_KEY=, chmod 600) and re-deploy jellyfin"
+    fi
+}
+
 deploy_jellyfin() {
     ensure_media_view
+    ensure_provider_keys
     cp "dankserver/jellyfin/quadlet/jellyfin.container" "$quadlet_unit_dir/"
     systemctl --user daemon-reload
     if ! systemctl --user is-active -q jellyfin.service; then