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-08c356bfcd7f7cd7a4bac0bf0ce44ce3276577cb18f32b0c01839150e7827bca.json

@@ -0,0 +1,12 @@
+{
+  "db_name": "SQLite",
+  "query": "INSERT INTO subtitle_attempts\n             (media_file_id, language, state, attempts, last_attempt_at, last_failure)\n         VALUES (?, ?, ?, 1, strftime('%Y-%m-%dT%H:%M:%fZ', 'now'), ?)\n         ON CONFLICT (media_file_id, language) DO UPDATE\n         SET state           = excluded.state,\n             attempts        = subtitle_attempts.attempts + 1,\n             last_attempt_at = excluded.last_attempt_at,\n             last_failure    = excluded.last_failure,\n             updated_at      = strftime('%Y-%m-%dT%H:%M:%fZ', 'now')",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Right": 4
+    },
+    "nullable": []
+  },
+  "hash": "08c356bfcd7f7cd7a4bac0bf0ce44ce3276577cb18f32b0c01839150e7827bca"
+}