kometa: a nightly scheduled run against plex, its credentials as files

ace runs Kometa under HAL as a long-lived container whose own scheduler wakes
at 03:00, with the Plex token and the TMDb key in its environment
(KOMETA_PLEX_TOKEN, KOMETA_TMDB_APIKEY). This is the case ADR 0053 was written
for: the module is one container marked "schedule": "0 3 * * *" that runs
kometa --run to completion, so nothing stays up between runs.

Secrets are files (ADR 0086): config.yml is rendered by the mesh, 0600 and
root-owned (Kometa runs as root), with ${secret:plex-api} and ${secret:tmdb}
in it, and mounted read-only. KOMETA_READ_ONLY_CONFIG stops Kometa writing its
defaults back into it (without it the run dies on EROFS); the file already
carries every attribute Kometa filled in on ace, so behaviour is unchanged.

Plex is reached through provisioning, not a URL: kometa requires plex-api
and reads ${bound:plex-api:at|port}; the token is that pair's credential,
which the operator accepts (ADR 0092). The provider half (plex provides and
serves plex-api, 32400) is NOT in this change: plex is outside this work, so
until plex declares it kometa cannot be assigned. The TMDb key is an
operator-accepted vault secret.

Which libraries Kometa manages is per machine: the manifest ships
"libraries": {}, and config.yml is the module's one merge:json file, so the
assignment supplies them (ace: the Formula 1 library, whose metadata file
comes from f1-circuits' public name).

Verified: catalogue tests with MESH_CATALOGUE pointed here, on mesh-controller
main and on #149; a resolution with stub providers renders the binding, the
two secret files and config.yml with the assignment's library merged in; the
pinned digest (the one ace runs, 2.4.8) in a throwaway container with the
rendered file root-owned 0600 read-only: config parses, the "endpoints" key is
tolerated, no write-back with the read-only flag, and the run stops only at
TMDb refusing the dummy key.

modules/kometa/module.json

@@ -0,0 +1,66 @@
+{
+  "module": "kometa",
+  "version": "1",
+  "capabilities": [
+    "container-runtime"
+  ],
+  "requires": [
+    "plex-api",
+    "secret"
+  ],
+  "binds": {
+    "plex-api": "${dir:state}/plex-api.json"
+  },
+  "secrets": {
+    "plex-api": "${dir:state}/plex-api.secret",
+    "secret": {
+      "tmdb": "${dir:state}/tmdb.secret"
+    }
+  },
+  "resources": [
+    {
+      "id": "state",
+      "type": "directory",
+      "mode": "0700",
+      "place": "."
+    },
+    {
+      "id": "config",
+      "type": "directory",
+      "mode": "0700"
+    },
+    {
+      "id": "settings",
+      "type": "file",
+      "path": "${dir:state}/config.yml",
+      "mode": "0600",
+      "merge": "json",
+      "content": "{\n  \"plex\": {\n    \"url\": \"http://${bound:plex-api:at}:${bound:plex-api:port}\",\n    \"token\": \"${secret:plex-api}\",\n    \"timeout\": 60,\n    \"clean_bundles\": false,\n    \"empty_trash\": false,\n    \"optimize\": false,\n    \"verify_ssl\": null,\n    \"db_cache\": null\n  },\n  \"tmdb\": {\n    \"apikey\": \"${secret:tmdb}\",\n    \"language\": \"en\",\n    \"cache_expiration\": 60,\n    \"region\": null\n  },\n  \"settings\": {\n    \"cache\": true,\n    \"cache_expiration\": 60,\n    \"asset_directory\": \"config/assets\",\n    \"sync_mode\": \"append\",\n    \"minimum_items\": 1,\n    \"delete_below_minimum\": false,\n    \"run_again_delay\": 2,\n    \"show_missing\": false,\n    \"save_report\": false,\n    \"run_order\": [\n      \"operations\",\n      \"metadata\",\n      \"collections\",\n      \"overlays\"\n    ],\n    \"asset_folders\": true,\n    \"asset_depth\": 0,\n    \"create_asset_folders\": false,\n    \"prioritize_assets\": false,\n    \"dimensional_asset_rename\": false,\n    \"download_url_assets\": false,\n    \"show_missing_assets\": true,\n    \"show_missing_season_assets\": false,\n    \"show_missing_episode_assets\": false,\n    \"show_asset_not_needed\": true,\n    \"default_collection_order\": null,\n    \"item_refresh_delay\": 0,\n    \"delete_not_scheduled\": false,\n    \"missing_only_released\": false,\n    \"only_filter_missing\": false,\n    \"show_unmanaged\": true,\n    \"show_unconfigured\": true,\n    \"show_filtered\": false,\n    \"show_unfiltered\": false,\n    \"show_options\": false,\n    \"tvdb_language\": \"default\",\n    \"ignore_ids\": null,\n    \"ignore_imdb_ids\": null,\n    \"playlist_sync_to_users\": null,\n    \"playlist_exclude_users\": null,\n    \"playlist_report\": true,\n    \"custom_repo\": null,\n    \"overlay_artwork_filetype\": \"webp_lossy\",\n    \"overlay_artwork_quality\": 90,\n    \"auto_sort_hubs\": null,\n    \"verify_ssl\": true\n  },\n  \"libraries\": {}\n}\n"
+    },
+    {
+      "id": "net",
+      "type": "network",
+      "name": "kometa"
+    },
+    {
+      "id": "run",
+      "type": "container",
+      "name": "kometa",
+      "image": "kometateam/kometa@sha256:6c3971a4aaa928b045e5f22514196b6db7f9b2b186158ebfe3239f4b328dfb0a",
+      "network": "kometa",
+      "schedule": "0 3 * * *",
+      "args": [
+        "--run"
+      ],
+      "env": {
+        "TZ": "Etc/UTC",
+        "KOMETA_NO_MISSING": "true",
+        "KOMETA_READ_ONLY_CONFIG": "true"
+      },
+      "volumes": [
+        "${dir:config}:/config",
+        "${dir:state}/config.yml:/config/config.yml:ro"
+      ]
+    }
+  ]
+}