feat(arr): add subtitle queries

Recording a subtitle is idempotent on both keys the schema carries: the
sidecar path, and the language an embedded track satisfies, so a second
probe or a re-import converges instead of duplicating. Attempts are
upserted per (media file, language); the work list is every language that
is not satisfied, newest import first, which is the order §15 wants the
daily allowance spent in.

.sqlx/query-6eaeee584dc98b28b9605faabab0eecf7839b7755c956731617b475921481701.json

@@ -0,0 +1,26 @@
+{
+  "db_name": "SQLite",
+  "query": "INSERT INTO subtitle_files\n               (media_file_id, language, origin, provider, candidate_id, engine,\n                forced, sdh, synced, sync_rejected, path)\n           VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)\n           ON CONFLICT DO NOTHING\n           RETURNING id AS \"id!: i64\"",
+  "describe": {
+    "columns": [
+      {
+        "name": "id!: i64",
+        "ordinal": 0,
+        "type_info": "Integer",
+        "origin": {
+          "Table": {
+            "table": "subtitle_files",
+            "name": "id"
+          }
+        }
+      }
+    ],
+    "parameters": {
+      "Right": 11
+    },
+    "nullable": [
+      null
+    ]
+  },
+  "hash": "6eaeee584dc98b28b9605faabab0eecf7839b7755c956731617b475921481701"
+}