Initial commit — Hamkadr (همکادر) healthcare-staffing marketplace

ASP.NET Core 10 Razor Pages + PostgreSQL/EF Core. RTL Persian, Jalali dates, self-hosted Vazirmatn, teal/coral brand.

Features:
- Shift listings: browse/filter (city, district, role, type, pay), weekly Jalali calendar, detail + interest handoff, near-me distance sort
- Hiring (استخدام) listings with employment type + salary range
- Pattern-engine recommendations + anonymous interest tracking (visitor cookie)
- Heuristic Persian listing-parser + admin queue (raw channel post → shift/job)
- Phone-OTP cookie auth + visitor-history linking + profile

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

src/JobsMedical.Web/Models/Visitor.cs

@@ -0,0 +1,23 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace JobsMedical.Web.Models;
+
+/// <summary>
+/// An anonymous visitor, identified by a cookie before they ever log in. This lets us track
+/// interest and personalize from the very first visit; once the person logs in we link the
+/// Visitor to their <see cref="User"/> and keep all the behavioral history.
+/// </summary>
+public class Visitor
+{
+    [MaxLength(36)]
+    public string Id { get; set; } = "";             // GUID string stored in the hk_vid cookie
+
+    public int? UserId { get; set; }                  // set after login (history carries over)
+    public User? User { get; set; }
+
+    public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
+    public DateTime LastSeenAt { get; set; } = DateTime.UtcNow;
+
+    public UserPreferences? Preferences { get; set; }
+    public ICollection<InterestEvent> Events { get; set; } = new List<InterestEvent>();
+}