Approximate-location map on aggregated listings (Divar coords)

We captured Divar's privacy-fuzzed coords on RawListing but discarded them for
the listings that need them: unnamed-facility shifts/jobs dropped them (to avoid
piling on the shared placeholder) and applicants had no coordinate field at all.

- Add Lat/Lng to Shift, JobOpening, TalentListing (migration ListingApproxCoords).
- Publish stores the source ad's approx coords on each aggregated listing.
- Detail pages render the map from the listing's own coords (fallback: facility),
  and aggregated coords show as a shaded «محدودهٔ تقریبی» circle (not a precise
  pin) via _NeshanMap data-approx, with a disclaimer. Applicants get a map card
  (they had none) + the page now loads the Neshan key.

Only Divar provides coords; the map needs NeshanMapKey set in admin settings.
Existing rows get coords once reprocessed (RawListing already has them).

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

src/JobsMedical.Web/Models/JobOpening.cs

@@ -40,6 +40,10 @@ public class JobOpening
     [MaxLength(500)]
     public string? SourceUrl { get; set; }
 
+    // APPROXIMATE coords from the source ad (Divar) for aggregated openings without a facility address.
+    public double? Lat { get; set; }
+    public double? Lng { get; set; }
+
     public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
 
     /// <summary>Contact channels harvested from the source ad (aggregated openings). When empty, the