feat(i18n): add ClaudeDo.Localization project with nested-JSON locale parser

tests/ClaudeDo.Localization.Tests/LocaleJsonTests.cs

@@ -0,0 +1,38 @@
+using ClaudeDo.Localization;
+
+namespace ClaudeDo.Localization.Tests;
+
+public class LocaleJsonTests
+{
+    private const string Sample = """
+    {
+      "metadata": { "code": "en", "name": "English" },
+      "settings": { "save": "Save", "general": { "model": "Model" } },
+      "tasks": { "addPlaceholder": "Add a task" }
+    }
+    """;
+
+    [Fact]
+    public void Parse_reads_metadata()
+    {
+        var f = LocaleJson.Parse(Sample);
+        Assert.Equal("en", f.Code);
+        Assert.Equal("English", f.Name);
+    }
+
+    [Fact]
+    public void Parse_flattens_nested_keys_to_dot_paths()
+    {
+        var f = LocaleJson.Parse(Sample);
+        Assert.Equal("Save", f.Strings["settings.save"]);
+        Assert.Equal("Model", f.Strings["settings.general.model"]);
+        Assert.Equal("Add a task", f.Strings["tasks.addPlaceholder"]);
+    }
+
+    [Fact]
+    public void Parse_excludes_metadata_from_strings()
+    {
+        var f = LocaleJson.Parse(Sample);
+        Assert.False(f.Strings.ContainsKey("metadata.code"));
+    }
+}