feat(i18n): add LocaleStore folder discovery

src/ClaudeDo.Localization/LocaleStore.cs

@@ -0,0 +1,31 @@
+namespace ClaudeDo.Localization;
+
+public sealed class LocaleStore
+{
+    private readonly Dictionary<string, LocaleFile> _byCode;
+
+    private LocaleStore(Dictionary<string, LocaleFile> byCode) => _byCode = byCode;
+
+    public IReadOnlyList<LocaleFile> Available => _byCode.Values.ToList();
+
+    public bool TryGet(string code, out LocaleFile? file) => _byCode.TryGetValue(code, out file);
+
+    public static LocaleStore Load(string folder)
+    {
+        var byCode = new Dictionary<string, LocaleFile>(StringComparer.OrdinalIgnoreCase);
+        if (Directory.Exists(folder))
+        {
+            foreach (var path in Directory.EnumerateFiles(folder, "*.json"))
+            {
+                try
+                {
+                    var file = LocaleJson.Parse(File.ReadAllText(path));
+                    if (!string.IsNullOrWhiteSpace(file.Code))
+                        byCode[file.Code] = file;
+                }
+                catch { /* skip malformed locale files */ }
+            }
+        }
+        return new LocaleStore(byCode);
+    }
+}

tests/ClaudeDo.Localization.Tests/LocaleStoreTests.cs

@@ -0,0 +1,38 @@
+using ClaudeDo.Localization;
+
+namespace ClaudeDo.Localization.Tests;
+
+public class LocaleStoreTests
+{
+    private static string WriteTempLocales(params (string file, string json)[] files)
+    {
+        var dir = Path.Combine(Path.GetTempPath(), "loc_" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(dir);
+        foreach (var (file, json) in files)
+            File.WriteAllText(Path.Combine(dir, file), json);
+        return dir;
+    }
+
+    [Fact]
+    public void Load_discovers_all_json_files()
+    {
+        var dir = WriteTempLocales(
+            ("en.json", """{ "metadata": { "code": "en", "name": "English" }, "a": { "b": "x" } }"""),
+            ("de.json", """{ "metadata": { "code": "de", "name": "Deutsch" }, "a": { "b": "y" } }"""));
+
+        var store = LocaleStore.Load(dir);
+
+        Assert.Equal(2, store.Available.Count);
+        Assert.True(store.TryGet("en", out var en));
+        Assert.Equal("x", en!.Strings["a.b"]);
+        Assert.True(store.TryGet("de", out var de));
+        Assert.Equal("Deutsch", de!.Name);
+    }
+
+    [Fact]
+    public void Load_returns_empty_when_folder_missing()
+    {
+        var store = LocaleStore.Load(Path.Combine(Path.GetTempPath(), "does_not_exist_" + Guid.NewGuid()));
+        Assert.Empty(store.Available);
+    }
+}