Move ingestion + Telegram/Bale/Divar config to DB-backed admin settings

- AppSetting gains source config: AutoIngestEnabled, IngestIntervalMinutes, Telegram/Bale/Divar enabled+channels/token/queries
- IListingSource.FetchAsync(AppSetting) — sources read config from DB, not IOptions/appsettings; sample source dev-only
- IngestionWorker reads AutoIngest+interval from DB each cycle (toggle at runtime, no redeploy)
- /Admin/Settings gets a 'منابع جمع‌آوری' section; removed Ingestion env/appsettings + compose env vars
- ENV_FILE shrinks to HOST_PORT + POSTGRES_* + ADMIN_PHONE (AI + sources are all in-admin); migration

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/JobsMedical.Web/appsettings.json

@@ -11,12 +11,5 @@
   },
   "Auth": {
     "AdminPhone": "09120000000"
-  },
-  "Ingestion": {
-    "Enabled": false,
-    "IntervalMinutes": 30,
-    "Telegram": { "Enabled": false, "BotToken": "", "Channels": [], "PerChannel": 20 },
-    "Bale": { "Enabled": false, "BotToken": "", "BaseUrl": "https://tapi.bale.ai" },
-    "Divar": { "Enabled": false, "City": "tehran", "Category": "jobs", "Queries": [], "BaseUrl": "https://api.divar.ir/v8/web-search", "PerQuery": 25 }
   }
 }