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/Data/ApplicationDbContext.cs

@@ -2,7 +2,6 @@ using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore;
 using TrueCV.Domain.Entities;
-using TrueCV.Domain.Enums;
 using TrueCV.Infrastructure.Identity;
 
 namespace TrueCV.Infrastructure.Data;
@@ -64,9 +63,6 @@ public class ApplicationDbContext : IdentityDbContext<ApplicationUser, IdentityR
                 .WithOne(f => f.CVCheck)
                 .HasForeignKey(f => f.CVCheckId)
                 .OnDelete(DeleteBehavior.Cascade);
-
-            // Ignore the User navigation property since we're using ApplicationUser
-            entity.Ignore(c => c.User);
         });
     }