feat(arr): reconcile subtitle gaps in the daemon

Closes each unsatisfied wanted language per DESIGN.md §8/§15: embedded
tracks satisfy for free (recording them as #189 left to this issue),
then provider search + ranked fetch + alass sync + sidecar write, then
immediate machine translation — extracting a text-format embedded track
when that is the only source — and otherwise the reason lands on the
attempt row for the missing-subtitles queue.

Closes run as detached tasks because alass and translation outlive the
25 s reconcile action budget; every outcome is recorded in domain rows
first, so a crash converges on the next tick. Failures back off on the
same §6.2 curve as movie searches; a rate-limited provider is the
'capped' queue state; unreachable providers and translators fold into
the existing §9.5 broken notification, edge-triggered.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.sqlx/query-caa03a8daf9064de5c4724fcfecf70cc13f9a188468395bf5558aa3068c8a4e4.json

@@ -0,0 +1,50 @@
+{
+  "db_name": "SQLite",
+  "query": "SELECT wanted_languages   AS \"wanted_languages!: String\",\n                  providers_enabled  AS \"providers_enabled!: String\",\n                  translation_engine AS \"translation_engine: String\"\n           FROM subtitle_settings WHERE id = 1",
+  "describe": {
+    "columns": [
+      {
+        "name": "wanted_languages!: String",
+        "ordinal": 0,
+        "type_info": "Text",
+        "origin": {
+          "Table": {
+            "table": "subtitle_settings",
+            "name": "wanted_languages"
+          }
+        }
+      },
+      {
+        "name": "providers_enabled!: String",
+        "ordinal": 1,
+        "type_info": "Text",
+        "origin": {
+          "Table": {
+            "table": "subtitle_settings",
+            "name": "providers_enabled"
+          }
+        }
+      },
+      {
+        "name": "translation_engine: String",
+        "ordinal": 2,
+        "type_info": "Text",
+        "origin": {
+          "Table": {
+            "table": "subtitle_settings",
+            "name": "translation_engine"
+          }
+        }
+      }
+    ],
+    "parameters": {
+      "Right": 0
+    },
+    "nullable": [
+      false,
+      false,
+      true
+    ]
+  },
+  "hash": "caa03a8daf9064de5c4724fcfecf70cc13f9a188468395bf5558aa3068c8a4e4"
+}