Add iranestekhdam.ir as an ingestion source (clinical job ads at named facilities)

New IranEstekhdamListingSource: reads the site monthly ad sitemaps
(sitemap-ads.xml -> sitemap-ads-YYYY-M.xml), keeps only ad URLs whose Persian slug names a
clinical role (veterinary/non-clinical excluded), then extracts each ad title + description
(+ phone). These are employer ads at NAMED facilities, so they directly improve the
unknown-facility problem the classifieds content has.

Wired in like Medjobs: AppSetting toggles (IranEstekhdamEnabled/MaxAds/UseProxy) + EF
migration, SettingsService persistence, admin Settings UI, and DI registration. Off by
default; the medical-gate validator + AI auditor + junk filters screen results downstream.

Note: e-estekhdam / jobinja / jobvision are JS-rendered SPAs whose ad lists are not in static
HTML, so they need API reverse-engineering (a separate effort), not this static-scrape path.

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

src/JobsMedical.Web/Migrations/AppDbContextModelSnapshot.cs

@@ -103,6 +103,15 @@ namespace JobsMedical.Web.Migrations
                         .HasMaxLength(1000)
                         .HasColumnType("character varying(1000)");
 
+                    b.Property<bool>("IranEstekhdamEnabled")
+                        .HasColumnType("boolean");
+
+                    b.Property<int>("IranEstekhdamMaxAds")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("IranEstekhdamUseProxy")
+                        .HasColumnType("boolean");
+
                     b.Property<bool>("MedjobsEnabled")
                         .HasColumnType("boolean");