Implement telemetry system with data collection and reporting

Signed-off-by: Dmitrii <computer@yawaflua.tech>

Took 20 minutes

backend/SpMega.Backend/Persistent/Database/AppDbContext.cs

@@ -1,5 +1,6 @@
 using Microsoft.EntityFrameworkCore;
 using MongoDB.EntityFrameworkCore.Extensions;
+using SpMega.Backend.Persistent.Models.Telemetry;
 using SpMega.Backend.Persistent.Models.Transactions;
 using SpMega.Backend.Persistent.Models.Users;
 using SpMega.Backend.Services;
@@ -11,6 +12,8 @@ public class AppDbContext(DbContextOptions<AppDbContext> options) : DbContext(op
     internal DbSet<Transaction> Transactions { get; set; }
     internal DbSet<User> Users { get; set; }
     internal DbSet<UserSession> UserSessions { get; set; }
+    internal DbSet<ModTelemetryDocument> ModTelemetry { get; set; }
+    internal DbSet<BackendRequestTelemetryDocument> BackendRequestTelemetry { get; set; }
 
     protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
     {

backend/SpMega.Backend/Persistent/Models/DTO/ModTelemetryBatchDto.cs

@@ -0,0 +1,16 @@
+using System.Text.Json;
+
+namespace SpMega.Backend.Persistent.Models.DTO;
+
+public record ModTelemetryEventDto(
+    string EventType,
+    DateTimeOffset Timestamp,
+    JsonElement Payload
+);
+
+public record ModTelemetryBatchDto(
+    string ClientVersion,
+    string SessionId,
+    DateTimeOffset SentAt,
+    List<ModTelemetryEventDto> Events
+);

backend/SpMega.Backend/Persistent/Models/Telemetry/BackendRequestTelemetryDocument.cs

@@ -0,0 +1,19 @@
+using MongoDB.Bson;
+
+namespace SpMega.Backend.Persistent.Models.Telemetry;
+
+public class BackendRequestTelemetryDocument
+{
+    public ObjectId Id { get; set; }
+    public string RequestId { get; set; } = string.Empty;
+    public string Method { get; set; } = string.Empty;
+    public string Path { get; set; } = string.Empty;
+    public string Scheme { get; set; } = string.Empty;
+    public string Host { get; set; } = string.Empty;
+    public string? ClientIp { get; set; }
+    public string? UserAgent { get; set; }
+    public int StatusCode { get; set; }
+    public long DurationMs { get; set; }
+    public string? UserId { get; set; }
+    public DateTimeOffset Timestamp { get; set; } = DateTimeOffset.UtcNow;
+}

backend/SpMega.Backend/Persistent/Models/Telemetry/ModTelemetryDocument.cs

@@ -0,0 +1,21 @@
+using MongoDB.Bson;
+
+namespace SpMega.Backend.Persistent.Models.Telemetry;
+
+public class ModTelemetryDocument
+{
+    public ObjectId Id { get; set; }
+    public string UserId { get; set; } = string.Empty;
+    public string SessionId { get; set; } = string.Empty;
+    public string ClientVersion { get; set; } = string.Empty;
+    public DateTimeOffset SentAt { get; set; }
+    public DateTimeOffset ReceivedAt { get; set; } = DateTimeOffset.UtcNow;
+    public List<ModTelemetryEventDocument> Events { get; set; } = [];
+}
+
+public class ModTelemetryEventDocument
+{
+    public string EventType { get; set; } = string.Empty;
+    public DateTimeOffset Timestamp { get; set; }
+    public string PayloadJson { get; set; } = "{}";
+}