Migrate legacy VB.NET service to modern C# Worker

Migrated the legacy VB.NET Windows Service to a modern C# Worker Service targeting .NET Framework 4.6.2. Key changes include:

- Added `Microsoft.Extensions.Hosting.WindowsServices`, `NLog`, and `Quartz` for logging and scheduling.
- Introduced `LogConfigFactory` to bridge `ServiceConfig` and `LogConfig` for Quartz jobs.
- Rewrote `Worker` to handle the full service lifecycle, including database connection, temp file management, and scheduler initialization.
- Implemented `SchedulerFinishEnvelope` and `SchedulerEnvelopeTaskApi` for Quartz job scheduling.
- Created `TempFiles` for service-level temp file management.
- Configured `NLog` for file and console logging.
- Updated `appsettings.json` for connection strings and service-specific configuration.
- Replaced legacy `ProjectInstaller` with `AddWindowsService()` for SCM integration.

EnvelopeGenerator.Service/LogConfigFactory.cs

@@ -0,0 +1,28 @@
+using DigitalData.Modules.Logging;
+
+namespace EnvelopeGenerator.Service;
+
+/// <summary>
+/// Builds a <see cref="LogConfig"/> from <see cref="ServiceConfig"/>.
+/// Required because CommonServices jobs have a hard dependency on <see cref="LogConfig"/>
+/// in their Quartz <c>JobDataMap</c>.
+/// Log path mirrors the legacy behavior: <c>&lt;BaseDirectory&gt;\Log</c>.
+/// </summary>
+internal static class LogConfigFactory
+{
+    public static LogConfig Create(ServiceConfig config)
+    {
+        var logPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Log");
+
+        var logConfig = new LogConfig(
+            LogConfig.PathType.CustomPath,
+            logPath,
+            null,
+            "Digital Data",
+            "EnvelopeGenerator.Service");
+
+        logConfig.Debug = config.Debug;
+
+        return logConfig;
+    }
+}