fix(co4e): section actions are text again, and "+ Mới" says it did something

* "+ Mới" / "Quản lý skill…" were full buttons, ~40px tall each — the
    loudest thing in a 230px sidebar, and three rows of height spent on
    them. The wireframe writes these as small accent text beside the
    heading; they are now 17px.

  * "+ Mới" looked broken. It was not: it replaces the canvas with a fresh
    empty flow, verified by loading a saved 3-node flow and pressing it
    (3 nodes → 0). But pressing it while the canvas ALREADY held an empty
    untitled flow produced an identical empty untitled flow — right, and
    invisible. It now focuses and selects the name field, and says
    "Flow mới — đặt tên rồi kéo agent vào canvas" in the status bar, so the
    press always has a visible result.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

i18n.py

@@ -2666,6 +2666,10 @@ STRINGS: Dict[str, Dict[str, str]] = {
         "en": "Show every flow run", "ja": "すべてのフロー実行を表示",
         "vi": "Xem toàn bộ lần chạy flow"},
     "co4e.back_to_flow": {"en": "Back to flow", "ja": "フローに戻る", "vi": "Về flow"},
+    "co4e.new_flow_ready": {
+        "en": "New flow — type a name, then drag agents onto the canvas",
+        "ja": "新しいフロー — 名前を入力し、エージェントをキャンバスへ",
+        "vi": "Flow mới — đặt tên rồi kéo agent vào canvas"},
     "co4e.tt_back_to_flow": {
         "en": "Back to the flow editor", "ja": "フローエディタに戻る",
         "vi": "Quay lại màn dựng flow"},