Add meeting workflow automation

MeetingAssistant/Workflow/FileMeetingWorkflowRulesProvider.cs

@@ -0,0 +1,60 @@
+using YamlDotNet.Serialization;
+using YamlDotNet.Serialization.NamingConventions;
+
+namespace MeetingAssistant.Workflow;
+
+public interface IMeetingWorkflowRulesProvider
+{
+    Task<IReadOnlyList<MeetingWorkflowRule>> GetRulesAsync(
+        MeetingAssistantOptions options,
+        CancellationToken cancellationToken);
+}
+
+public sealed class FileMeetingWorkflowRulesProvider : IMeetingWorkflowRulesProvider
+{
+    private readonly ILogger<FileMeetingWorkflowRulesProvider> logger;
+    private readonly IDeserializer yamlDeserializer = new DeserializerBuilder()
+        .WithNamingConvention(UnderscoredNamingConvention.Instance)
+        .IgnoreUnmatchedProperties()
+        .Build();
+
+    public FileMeetingWorkflowRulesProvider(ILogger<FileMeetingWorkflowRulesProvider> logger)
+    {
+        this.logger = logger;
+    }
+
+    public async Task<IReadOnlyList<MeetingWorkflowRule>> GetRulesAsync(
+        MeetingAssistantOptions options,
+        CancellationToken cancellationToken)
+    {
+        if (string.IsNullOrWhiteSpace(options.Automation.RulesPath))
+        {
+            return [];
+        }
+
+        var path = ResolvePath(options.Automation.RulesPath);
+        if (!File.Exists(path))
+        {
+            logger.LogDebug("Meeting workflow rules file {RulesPath} does not exist", path);
+            return [];
+        }
+
+        var yaml = await File.ReadAllTextAsync(path, cancellationToken);
+        if (string.IsNullOrWhiteSpace(yaml))
+        {
+            return [];
+        }
+
+        var rulesFile = yamlDeserializer.Deserialize<MeetingWorkflowRulesFile>(yaml)
+            ?? new MeetingWorkflowRulesFile();
+        return rulesFile.Rules;
+    }
+
+    private static string ResolvePath(string configuredPath)
+    {
+        var expanded = Environment.ExpandEnvironmentVariables(configuredPath);
+        return Path.IsPathRooted(expanded)
+            ? Path.GetFullPath(expanded)
+            : Path.GetFullPath(expanded);
+    }
+}