feat: complete release readiness work

- consolidate API ownership and remove dead vendor code

- add Stripe billing, learning paths, and public CV hardening

- add migration, recovery, security, audit, and browser gates

JobTrackerApi/Models/JobEvent.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Text.Json.Serialization;
+
+namespace JobTrackerApi.Models
+{
+    public class JobEvent
+    {
+        public int Id { get; set; }
+        public int JobApplicationId { get; set; }
+
+        [JsonIgnore]
+        public JobApplication JobApplication { get; set; } = null!;
+
+        public string Type { get; set; } = ""; // Created, StatusChanged, FollowUpSet, Deleted, Restored
+        public string? OldValue { get; set; }
+        public string? NewValue { get; set; }
+        public string? Note { get; set; }
+        public DateTime At { get; set; } = DateTime.Now;
+    }
+}