Phase 8: Production readiness — failover tests, security hardening, sandboxing, deployment docs

- WP-1-3: Central/site failover + dual-node recovery tests (17 tests)
- WP-4: Performance testing framework for target scale (7 tests)
- WP-5: Security hardening (LDAPS, JWT key length, no secrets in logs) (11 tests)
- WP-6: Script sandboxing adversarial tests (28 tests, all forbidden APIs)
- WP-7: Recovery drill test scaffolds (5 tests)
- WP-8: Observability validation (structured logs, correlation IDs, metrics) (6 tests)
- WP-9: Message contract compatibility (forward/backward compat) (18 tests)
- WP-10: Deployment packaging (installation guide, production checklist, topology)
- WP-11: Operational runbooks (failover, troubleshooting, maintenance)
92 new tests, all passing. Zero warnings.

src/ScadaLink.ConfigurationDatabase/Repositories/ExternalSystemRepository.cs

@@ -0,0 +1,72 @@
+using Microsoft.EntityFrameworkCore;
+using ScadaLink.Commons.Entities.ExternalSystems;
+using ScadaLink.Commons.Interfaces.Repositories;
+
+namespace ScadaLink.ConfigurationDatabase.Repositories;
+
+public class ExternalSystemRepository : IExternalSystemRepository
+{
+    private readonly ScadaLinkDbContext _context;
+
+    public ExternalSystemRepository(ScadaLinkDbContext context)
+    {
+        _context = context;
+    }
+
+    public async Task<ExternalSystemDefinition?> GetExternalSystemByIdAsync(int id, CancellationToken cancellationToken = default)
+        => await _context.Set<ExternalSystemDefinition>().FindAsync(new object[] { id }, cancellationToken);
+
+    public async Task<IReadOnlyList<ExternalSystemDefinition>> GetAllExternalSystemsAsync(CancellationToken cancellationToken = default)
+        => await _context.Set<ExternalSystemDefinition>().ToListAsync(cancellationToken);
+
+    public async Task AddExternalSystemAsync(ExternalSystemDefinition definition, CancellationToken cancellationToken = default)
+        => await _context.Set<ExternalSystemDefinition>().AddAsync(definition, cancellationToken);
+
+    public Task UpdateExternalSystemAsync(ExternalSystemDefinition definition, CancellationToken cancellationToken = default)
+    { _context.Set<ExternalSystemDefinition>().Update(definition); return Task.CompletedTask; }
+
+    public async Task DeleteExternalSystemAsync(int id, CancellationToken cancellationToken = default)
+    {
+        var entity = await GetExternalSystemByIdAsync(id, cancellationToken);
+        if (entity != null) _context.Set<ExternalSystemDefinition>().Remove(entity);
+    }
+
+    public async Task<ExternalSystemMethod?> GetExternalSystemMethodByIdAsync(int id, CancellationToken cancellationToken = default)
+        => await _context.Set<ExternalSystemMethod>().FindAsync(new object[] { id }, cancellationToken);
+
+    public async Task<IReadOnlyList<ExternalSystemMethod>> GetMethodsByExternalSystemIdAsync(int externalSystemId, CancellationToken cancellationToken = default)
+        => await _context.Set<ExternalSystemMethod>().Where(m => m.ExternalSystemDefinitionId == externalSystemId).ToListAsync(cancellationToken);
+
+    public async Task AddExternalSystemMethodAsync(ExternalSystemMethod method, CancellationToken cancellationToken = default)
+        => await _context.Set<ExternalSystemMethod>().AddAsync(method, cancellationToken);
+
+    public Task UpdateExternalSystemMethodAsync(ExternalSystemMethod method, CancellationToken cancellationToken = default)
+    { _context.Set<ExternalSystemMethod>().Update(method); return Task.CompletedTask; }
+
+    public async Task DeleteExternalSystemMethodAsync(int id, CancellationToken cancellationToken = default)
+    {
+        var entity = await GetExternalSystemMethodByIdAsync(id, cancellationToken);
+        if (entity != null) _context.Set<ExternalSystemMethod>().Remove(entity);
+    }
+
+    public async Task<DatabaseConnectionDefinition?> GetDatabaseConnectionByIdAsync(int id, CancellationToken cancellationToken = default)
+        => await _context.Set<DatabaseConnectionDefinition>().FindAsync(new object[] { id }, cancellationToken);
+
+    public async Task<IReadOnlyList<DatabaseConnectionDefinition>> GetAllDatabaseConnectionsAsync(CancellationToken cancellationToken = default)
+        => await _context.Set<DatabaseConnectionDefinition>().ToListAsync(cancellationToken);
+
+    public async Task AddDatabaseConnectionAsync(DatabaseConnectionDefinition definition, CancellationToken cancellationToken = default)
+        => await _context.Set<DatabaseConnectionDefinition>().AddAsync(definition, cancellationToken);
+
+    public Task UpdateDatabaseConnectionAsync(DatabaseConnectionDefinition definition, CancellationToken cancellationToken = default)
+    { _context.Set<DatabaseConnectionDefinition>().Update(definition); return Task.CompletedTask; }
+
+    public async Task DeleteDatabaseConnectionAsync(int id, CancellationToken cancellationToken = default)
+    {
+        var entity = await GetDatabaseConnectionByIdAsync(id, cancellationToken);
+        if (entity != null) _context.Set<DatabaseConnectionDefinition>().Remove(entity);
+    }
+
+    public async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
+        => await _context.SaveChangesAsync(cancellationToken);
+}