Initial Commit after switching from SVN to git

.github/instructions/periodic_service.instructions.md

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+---
+applyTo: "Fuchs_DataService/**"
+---
+
+# PeriodicHostedService Instructions
+
+## Overview
+`PeriodicHostedService` (`Fuchs_DataService/PeriodicHostedService.cs`) is a `BackgroundService` that runs multiple independent jobs, each on its own `PeriodicTimer`. It is started and stopped by the Topshelf `FdsService` (see `topshelf.instructions.md`).
+
+## Job Definition
+Each job is a `PeriodicJobDefinition` record:
+```csharp
+public sealed record PeriodicJobDefinition(
+    string Name,
+    TimeSpan Interval,
+    Func<CancellationToken, Task> Execute);
+```
+
+## Registering Jobs
+Jobs are created in `FdsService` constructor and passed to `PeriodicHostedService`:
+```csharp
+var interval = TimeSpan.FromMinutes(FdsConfig.ExecutionFrequency_Minutes);
+var jobs = new[]
+{
+    new PeriodicJobDefinition("MfrSync", interval, async ct =>
+    {
+        await mfr.UpdateIfNecessary_async(debug);
+        await mfr.UpdateRequested_async(debug);
+        await mfr.GetInvoiceFiles_async(debug);
+    }),
+    // Add more jobs with different schedules here:
+    // new PeriodicJobDefinition("HourlyJob", TimeSpan.FromHours(1), async ct => { ... })
+};
+```
+
+## Schedules
+- Each job runs on its **own independent `PeriodicTimer`** — schedules do not interfere.
+- Frequencies are configured in `appsettings.json` under the `Fds` section (e.g. `Fds:ExecutionFrequency_Minutes`).
+- Add new config keys for additional job intervals as needed.
+
+## Error Handling
+- Each job's `Execute` delegate is wrapped in a `try/catch` inside `RunJobAsync`.
+- `OperationCanceledException` propagates normally (signals shutdown).
+- All other exceptions are caught, logged via `ILogger`, and the job continues on its next tick.
+
+## Cancellation
+- `PeriodicHostedService` respects the `CancellationToken` passed to `StartAsync`.
+- `FdsService.Stop()` cancels the token, then awaits `StopAsync(CancellationToken.None)`.
+
+## Adding a New Job
+1. Optionally add a new frequency key to `appsettings.json` and read it via `FdsConfig`.
+2. Add a new `PeriodicJobDefinition` to the `jobs` array in `FdsService`.
+3. No changes to `PeriodicHostedService` itself are needed.