fix(cli): show the platform's default watch settle time

src/Filee.Cli/Help.cs

@@ -1,6 +1,7 @@
 // Usage text of the "filee" command.
 
 using System.Reflection;
+using Filee.Core.Watching;
 
 namespace Filee.Cli;
 
@@ -61,7 +62,7 @@ Files can be wildcards (*.heic). Folders convert the files in them that Filee kn
 
         """;
 
-    private const string Watch = """
+    private static string Watch => FormattableString.Invariant($"""
         Usage: filee watch <folder> (--to <format> | --preset <preset>) [options]
 
         Converts files that land in the folder until Ctrl+C. Files are converted once they are complete (no
@@ -74,10 +75,10 @@ Files can be wildcards (*.heic). Folders convert the files in them that Filee kn
           -r, --recursive        Also watch sub folders (their files keep the sub folder in the output)
               --move-originals   Move converted sources to <folder>\originals; files already waiting are
                                  converted at start
-              --settle <seconds> How long a file must stay unchanged (default 2)
+              --settle <seconds> How long a file must stay unchanged (default {FolderWatcher.DefaultSettleTime.TotalSeconds})
               --keep-dates       Give converted files the created and modified dates of the originals
               --zip              Save the result of each file as one ZIP (a Shapefile's files together)
               --quiet            Print nothing but errors
 
-        """;
+        """);
 }

tests/Filee.Cli.Tests/HelpTests.cs

@@ -0,0 +1,26 @@
+// CLI help must describe the watcher's platform default without loading settings or engines.
+
+using Filee.Core.Watching;
+
+namespace Filee.Cli.Tests;
+
+public sealed class HelpTests
+{
+    [Theory]
+    [InlineData("help", "watch")]
+    [InlineData("watch", "--help")]
+    [InlineData("watch", "-h")]
+    public async Task Watch_help_reports_the_platform_default_without_loading_engines(string command, string option)
+    {
+        var output = new StringWriter();
+        var errors = new StringWriter();
+
+        var code = await Cli.RunAsync([command, option], output, errors, TestContext.Current.CancellationToken,
+            () => throw new InvalidOperationException("Help must not initialize engines."));
+
+        Assert.Equal(Cli.Success, code);
+        Assert.Equal("", errors.ToString());
+        Assert.Contains(FormattableString.Invariant(
+            $"--settle <seconds> How long a file must stay unchanged (default {FolderWatcher.DefaultSettleTime.TotalSeconds})"), output.ToString());
+    }
+}