데스크톱 T3 잔여 완성 + 스타일 폴리시: 도메인 라우팅(WorkspaceRoutingRules 자동 워크스페이스 전환), 탭 아카이브(TabArchive 영속·팔레트 복구), 페이지 액션(흑백/세피아 필터), 노트 패널(NotesStore+플라이아웃), 컴팩트 모드(크롬 숨김+엣지 호버). 스타일: 한국어 폰트 폴백, 암시 폰트 통일, 다크 툴팁, 텍스트 대비 상향. UpdateNavState dispose 가드. 164/164 GREEN + 실창 스크린샷 검증

VideoDownloader.Browser/NotesStore.cs

@@ -0,0 +1,63 @@
+using System.Text.Json;
+
+namespace VideoDownloader.Browser;
+
+public sealed record NoteItem(string Id, string Title, string Body, DateTime CreatedAt);
+
+/// <summary>T3-12: 노트 패널 저장소 — 마크다운 텍스트 노트 추가·검색·삭제, JSON 영속.</summary>
+public sealed class NotesStore
+{
+    private readonly string _path;
+    private readonly object _gate = new();
+    private List<NoteItem> _items;
+
+    public NotesStore(string path)
+    {
+        _path = path;
+        try
+        {
+            if (File.Exists(path))
+                _items = JsonSerializer.Deserialize<List<NoteItem>>(File.ReadAllText(path)) ?? new();
+        }
+        catch { }
+        _items ??= new List<NoteItem>();
+    }
+
+    public string Add(string title, string body)
+    {
+        var note = new NoteItem(Guid.NewGuid().ToString("N"), title, body, DateTime.Now);
+        lock (_gate)
+        {
+            _items.Insert(0, note);
+            try
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(_path)!);
+                File.WriteAllText(_path, JsonSerializer.Serialize(_items));
+            }
+            catch { }
+        }
+        return note.Id;
+    }
+
+    public List<NoteItem> List()
+    {
+        lock (_gate) return _items.ToList();
+    }
+
+    public List<NoteItem> Search(string query)
+    {
+        var q = query?.Trim() ?? "";
+        return List().Where(n => q.Length == 0 ||
+            n.Title.Contains(q, StringComparison.OrdinalIgnoreCase) ||
+            n.Body.Contains(q, StringComparison.OrdinalIgnoreCase)).ToList();
+    }
+
+    public void Delete(string id)
+    {
+        lock (_gate)
+        {
+            _items.RemoveAll(n => n.Id == id);
+            try { File.WriteAllText(_path, JsonSerializer.Serialize(_items)); } catch { }
+        }
+    }
+}

VideoDownloader.Browser/TabArchive.cs

@@ -0,0 +1,63 @@
+using System.Text.Json;
+
+namespace VideoDownloader.Browser;
+
+public sealed record ArchivedTab(string Title, string Url, DateTime ClosedAt);
+
+/// <summary>T3-2: 탭 아카이브 — 닫힘 이력 영속(최대 500, 같은 URL 연속은 제목 갱신), 검색·복구 지원.</summary>
+public sealed class TabArchive
+{
+    private const int Cap = 500;
+    private readonly string _path;
+    private readonly object _gate = new();
+    private List<ArchivedTab> _items;
+
+    public TabArchive(string path)
+    {
+        _path = path;
+        try
+        {
+            if (File.Exists(path))
+                _items = JsonSerializer.Deserialize<List<ArchivedTab>>(File.ReadAllText(path)) ?? new();
+        }
+        catch { }
+        _items ??= new List<ArchivedTab>();
+    }
+
+    public void Add(string title, string url)
+    {
+        if (string.IsNullOrWhiteSpace(url)) return;
+        lock (_gate)
+        {
+            _items.RemoveAll(t => t.Url.Equals(url, StringComparison.OrdinalIgnoreCase));
+            _items.Insert(0, new ArchivedTab(title, url, DateTime.Now));
+            if (_items.Count > Cap) _items.RemoveRange(Cap, _items.Count - Cap);
+            try
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(_path)!);
+                File.WriteAllText(_path, JsonSerializer.Serialize(_items));
+            }
+            catch { }
+        }
+    }
+
+    public List<ArchivedTab> Search(string query)
+    {
+        lock (_gate)
+        {
+            var q = query?.Trim() ?? "";
+            return _items.Where(t => q.Length == 0 ||
+                t.Title.Contains(q, StringComparison.OrdinalIgnoreCase) ||
+                t.Url.Contains(q, StringComparison.OrdinalIgnoreCase)).ToList();
+        }
+    }
+
+    public void Remove(string url)
+    {
+        lock (_gate)
+        {
+            _items.RemoveAll(t => t.Url.Equals(url, StringComparison.OrdinalIgnoreCase));
+            try { File.WriteAllText(_path, JsonSerializer.Serialize(_items)); } catch { }
+        }
+    }
+}

VideoDownloader.Browser/WorkspaceRoutingRules.cs

@@ -0,0 +1,65 @@
+using System.Text.Json;
+
+namespace VideoDownloader.Browser;
+
+/// <summary>T3-1: 도메인 → 워크스페이스 자동 라우팅 규칙(Vivaldi 규칙/Arc ATC).
+/// 주소창 이동 시 매칭되면 해당 워크스페이스로 자동 전환한다. JSON 영속.</summary>
+public sealed class WorkspaceRoutingRules
+{
+    private readonly string _path;
+    private Dictionary<string, string> _map = new(StringComparer.OrdinalIgnoreCase);
+
+    public WorkspaceRoutingRules(string path)
+    {
+        _path = path;
+        try
+        {
+            if (File.Exists(path))
+                _map = JsonSerializer.Deserialize<Dictionary<string, string>>(File.ReadAllText(path)) ?? new();
+        }
+        catch { }
+        _map ??= new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+    }
+
+    public IReadOnlyDictionary<string, string> Rules => _map;
+
+    public void Add(string domain, string workspaceName)
+    {
+        var d = domain.Trim().TrimStart('.', 'w', 'w', 'w', '.');
+        _map[d] = workspaceName;
+        Save();
+    }
+
+    public void Remove(string domain)
+    {
+        _map.Remove(domain.Trim());
+        Save();
+    }
+
+    /// <summary>URL 이 매칭되는 워크스페이스명(없으면 null). www/서브도메인 허용.</summary>
+    public string? Match(string? url)
+    {
+        if (string.IsNullOrWhiteSpace(url)) return null;
+        if (!Uri.TryCreate(url, UriKind.Absolute, out var u) ||
+            (u.Scheme != Uri.UriSchemeHttp && u.Scheme != Uri.UriSchemeHttps)) return null;
+        var host = u.Host;
+        if (host.StartsWith("www.", StringComparison.OrdinalIgnoreCase)) host = host[4..];
+        foreach (var (domain, ws) in _map)
+        {
+            if (host.Equals(domain, StringComparison.OrdinalIgnoreCase) ||
+                host.EndsWith("." + domain, StringComparison.OrdinalIgnoreCase))
+                return ws;
+        }
+        return null;
+    }
+
+    private void Save()
+    {
+        try
+        {
+            Directory.CreateDirectory(Path.GetDirectoryName(_path)!);
+            File.WriteAllText(_path, JsonSerializer.Serialize(_map));
+        }
+        catch { }
+    }
+}