Add UK education verification and security fixes

Features:
- Add UK institution recognition (170+ universities)
- Add diploma mill detection (100+ blacklisted institutions)
- Add education verification service with date plausibility checks
- Add local file storage option (no Azure required)
- Add default admin user seeding on startup
- Enhance Serilog logging with file output

Security fixes:
- Fix path traversal vulnerability in LocalFileStorageService
- Fix open redirect in login endpoint (use LocalRedirect)
- Fix password validation message (12 chars, not 6)
- Fix login to use HTTP POST endpoint (avoid Blazor cookie issues)

Code improvements:
- Add CancellationToken propagation to CV parser
- Add shared helpers (JsonDefaults, DateHelpers, ScoreThresholds)
- Add IUserContextService for user ID extraction
- Parallelized company verification in ProcessCVCheckJob
- Add 28 unit tests for education verification

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/TrueCV.Infrastructure/Services/CVCheckService.cs

@@ -3,6 +3,7 @@ using Hangfire;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
 using TrueCV.Application.DTOs;
+using TrueCV.Application.Helpers;
 using TrueCV.Application.Interfaces;
 using TrueCV.Application.Models;
 using TrueCV.Domain.Entities;
@@ -139,7 +140,7 @@ public sealed class CVCheckService : ICVCheckService
 
         try
         {
-            var report = JsonSerializer.Deserialize<VeracityReport>(cvCheck.ReportJson);
+            var report = JsonSerializer.Deserialize<VeracityReport>(cvCheck.ReportJson, JsonDefaults.CamelCase);
             return report;
         }
         catch (JsonException ex)