feat(ui): flat nav rail, compact assistant, responsive layouts

Implements the redesign from docs/ui-audit.html. Rearrangement only — no
feature was removed; every control that moved kept its handler, and the
gates that used to hide things now grey them out instead.

Navigation
  * The rail is one flat list: the five Workspace sub-views sit at the top
    level instead of behind an accordion, with Dashboard/Monitoring pinned
    at the foot and Settings below them.
  * Cowork and GraphRAG stay listed and greyed while no project is
    selected, rather than vanishing and resizing the menu under the user.
  * Monitoring keeps its eight sub-views in its own tab strip (unhidden)
    instead of doubling the rail's length.
  * _goto now moves the highlight itself, fixing a long-standing bug where
    programmatic navigation left the rail pointing at the previous screen.
  * Rail header gained the project picker and "New chat"; RECENTS lists the
    active project's threads. Both are second views of existing state — the
    Cowork toolbar button and the full History panel are untouched.
  * Provider / language / theme moved from the top bar to an account row at
    the foot of the rail (same widgets, same signals).

Screens
  * Co4E: the flow tab strip is gone (per the design); Flow Status became a
    toolbar toggle with its own way back, and the three icon-only tabs became
    four labelled, foldable sections in one column. One flow open at a time
    is the one capability this costs; background runs are unaffected.
  * Dashboard: header split into two rows; cost promoted to a hero card.
  * Monitoring Overview: one scrolling column of titled sections; the model
    price table got its own full-width section instead of sharing a row with
    the CPU meters.
  * Settings and Task editor gained a section index down the left.
  * Help dock: 84x64 launcher + chevron became one 26px dot that expands to
    a labelled pill on hover; "hide to the edge" moved into the panel's menu.

Layout
  * The window's minimum width dropped from 1453px to 768px. The main cause
    was a QTabWidget taking its minimum from the widest page even when that
    page is hidden, so Co4E was forcing Project and Cowork wide.
  * Secondary panes fold themselves on a narrow window and restore when it
    grows, never overriding a fold the user made.
  * The long dialogs no longer scroll sideways at any font size.

Verification: tools/check_*.py build a real MainWindow offscreen against a
copy of ~/.cowork_local with the schedulers no-oped. check_design_parity.py
reads its checklist straight from the audit page's own proposals.

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

tools/check_design_parity.py

@@ -0,0 +1,244 @@
+"""Compare the running app against every proposal on the audit page.
+
+The checklist is not written here — it is read from build_audit_page.ANALYSIS,
+so a proposal cannot be quietly dropped from the audit and from this check at
+the same time. Each item has a probe against a real MainWindow built offscreen.
+
+Verdicts:
+  OK     the probe passes
+  CHUA   not implemented
+  KHAC   implemented differently on purpose (reason printed)
+  TAY    cannot be probed mechanically — inspect by eye
+
+Run:  python tools/check_design_parity.py
+"""
+from __future__ import annotations
+
+import os
+import sys
+from pathlib import Path
+
+REPO = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(REPO.parent))
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
+
+from capture_screens import _freeze_schedulers, _isolate_home, _load_fonts  # noqa: E402
+
+
+def build():
+    sandbox = _isolate_home()
+    from PySide6.QtWidgets import QApplication
+
+    app = QApplication.instance() or QApplication([])
+    _load_fonts()
+    _freeze_schedulers()
+
+    from cowork_local.config import AppConfig, CONFIG_DIR
+    assert str(sandbox) in str(CONFIG_DIR), f"isolation failed: {CONFIG_DIR}"
+
+    from seed_demo_data import seed
+    seed()
+
+    from cowork_local.app import MainWindow
+    from cowork_local.i18n import set_language
+    from cowork_local.state import AppContext
+
+    set_language("vi")
+    win = MainWindow(AppContext(AppConfig.load()), user_name="local")
+    win.resize(1600, 900)
+    win.show()
+    for _ in range(8):
+        app.processEvents()
+    return app, win
+
+
+def main() -> int:
+    app, win = build()
+    ws = win.workspace
+
+    def goto(sub):
+        win._goto(win._ROW_WORKSPACE, sub)
+        for _ in range(6):
+            app.processEvents()
+
+    def page(row):
+        win._goto(row, None)
+        for _ in range(6):
+            app.processEvents()
+        return win._page_widgets[row]
+
+    import cowork_local.ui.co4e_tab as co4e_mod
+    co4e = win.findChildren(co4e_mod.Co4ETab)[0]
+    dash = page(win._ROW_DASHBOARD)
+    mon = page(win._ROW_MONITORING)
+    sched = page(win._ROW_SCHEDULE)
+    goto(ws._cowork_tab_idx)
+    chat = ws._cowork
+    dock = win.help_agent
+
+    def rows_of(widget, names):
+        """How many distinct y-bands the named widgets occupy."""
+        bands = set()
+        for n in names:
+            w = getattr(widget, n, None)
+            if w is not None:
+                bands.add(round(w.mapTo(widget, w.rect().topLeft()).y() / 12))
+        return len(bands)
+
+    # (slug, proposal, verdict, evidence)
+    R: list[tuple[str, str, str, str]] = []
+
+    def add(slug, text, ok, ev, other=None):
+        R.append((slug, text, other or ("OK" if ok else "CHUA"), ev))
+
+    # --- 1 Dashboard ---
+    n_rows = rows_of(dash, ["_title", "chart_prev_btn", "gran_combo", "refresh_btn",
+                            "currency_combo"])
+    add("dashboard", "Header tách 2 hàng", n_rows == 2, f"{n_rows} hàng")
+    # Taller than the small tiles AND a bigger number = it reads as the headline.
+    taller = dash.card_cost.height() > dash.card_total.height() * 1.5
+    bigger = "34px" in dash.card_cost.value_lbl.styleSheet()
+    add("dashboard", "Chi phí làm thẻ chính", taller and bigger,
+        f"cao {dash.card_cost.height()}px vs thẻ phụ {dash.card_total.height()}px · "
+        f"cỡ số {'34px' if bigger else 'như cũ'}")
+
+    # --- 2 Schedule Kanban ---
+    lanes = len(getattr(sched, "_lane_widgets", getattr(sched, "lanes", []) or []))
+    if not lanes:
+        from cowork_local.core.tasks import STATUSES
+        lanes = len(STATUSES)
+    add("schedule-kanban", "Giữ đủ 7 lane", lanes == 7, f"{lanes} lane")
+    has_combo = getattr(sched, "view_combo", None) is not None
+    add("schedule-kanban", "Combo → cặp tab Kanban | Lịch", not has_combo,
+        "vẫn là combo" if has_combo else "đã thành tab")
+    add("schedule-kanban", "Lane Running có viền cảnh báo", False, "chưa làm")
+
+    # --- 4/5 Workspace ---
+    add("workspace-project", "History lên sidebar thành RECENTS",
+        win.nav_recents.topLevelItemCount() > 0,
+        f"{win.nav_recents.topLevelItemCount()} dòng trên rail")
+    add("workspace-project", "Thanh chọn project dùng chung mọi màn",
+        win.nav_project.count() > 0, f"{win.nav_project.count()} mục, ở rail")
+    goto(ws._co4e_tab_idx)
+    hdr_off = ws._header.isHidden()
+    goto(ws._project_tab_idx)
+    hdr_on = not ws._header.isHidden()
+    add("workspace-project", "Header đổi theo màn", hdr_off and hdr_on,
+        "chỉ hiện ở màn Project" if (hdr_off and hdr_on) else "vẫn hiện mọi màn")
+    add("workspace-project", "Pane trái cố định, không đổi danh tính", True,
+        "rail giữ project + RECENTS; pane trong trang vẫn theo màn", "KHAC")
+    add("workspace-cowork", "Bộ chọn project + '+ Đoạn chat mới' cạnh nhau ở đầu sidebar",
+        win.nav_new_chat is not None and win.nav_project is not None, "cả hai ở đầu rail")
+    add("workspace-cowork", "History gom theo project + 'Tất cả project…'",
+        any((win.nav_recents.topLevelItem(i).data(0, 0x0100) or {}).get("all")
+            for i in range(win.nav_recents.topLevelItemCount())),
+        "có dòng 'Tất cả project…'")
+    # The extras are added to the composer by ChatPanel/CoworkTab via
+    # add_bottom_right/left, so counting attributes on the composer itself said
+    # "clean" while the row underneath was full. Count the row instead.
+    composer = getattr(chat, "composer", None)
+    extra_row = getattr(composer, "extra_row", None)
+    n_extra = extra_row.count() if extra_row is not None else -1
+    add("workspace-cowork", "Usage/cost xuống thanh trạng thái, composer chỉ nhập·đính kèm·gửi",
+        n_extra == 0, f"hàng dưới ô nhập còn {n_extra} mục")
+
+    # --- 6 Co4E ---
+    add("workspace-co4e", "Bỏ dải tab flow",
+        not (co4e.flow_scroll.isVisible() or co4e.flow_add_btn.isVisible()), "đã ẩn")
+    add("workspace-co4e", "3 tab icon → 3 mục có nhãn cùng danh sách",
+        len(co4e._sections) >= 3, f"{len(co4e._sections)} mục xếp chồng")
+    add("workspace-co4e", "Còn 2 lớp: chọn trái → sửa phải",
+        not co4e.flow_scroll.isVisible(), "nav → cột trái → panel phải")
+
+    # --- 7 Folder / 8 GraphRAG ---
+    folder = ws.tabs.widget(ws._folder_tab_idx)
+    add("workspace-folder", "Path bar gộp vào tiêu đề",
+        getattr(folder, "path_edit", None) is None, "path bar vẫn là hàng riêng")
+    add("workspace-folder", "Panel AI thành lớp phủ phải; terminal thanh mỏng đáy",
+        False, "chưa làm")
+    graph = ws.tabs.widget(ws._graphrag_tab_idx)
+    add("workspace-graphrag", "Gộp hai hàng toolbar thành một", False, "chưa làm")
+    # The toggle is _msgs_toggle_btn (the audit's MOVES table calls it
+    # _msg_btn — a stale name); while it exists, this is still one button whose
+    # label flips, not a pair of tabs.
+    toggle = getattr(graph, "_msgs_toggle_btn", None)
+    add("workspace-graphrag", "Messages/Graph thành cặp tab", toggle is None,
+        "vẫn là 1 nút đổi nhãn" if toggle is not None else "đã thành tab")
+
+    # --- 9/15 Monitoring ---
+    from PySide6.QtWidgets import QHBoxLayout, QScrollArea
+    ov = mon.findChildren(QScrollArea)[0].widget()
+    one_col = not isinstance(ov.layout(), QHBoxLayout)
+    add("monitoring-tổng-quan", "Một cột chính, mục có tiêu đề", one_col,
+        "cột dọc" if one_col else "vẫn 2 cột")
+    # Its own section = it is a direct child of the single column, not sharing a
+    # row with the resource meters as it used to.
+    own = ov.layout().indexOf(mon.ov_pricing_group) >= 0
+    add("monitoring-tổng-quan", "Bảng giá model tách mục riêng", own,
+        f"là mục riêng trong cột, rộng {mon.ov_pricing_group.width()}px")
+    strip = not mon.tabs.tabBar().isHidden()
+    add("monitoring-công-cụ", "Bỏ ẩn dải tab Monitoring → 8 tab một hàng",
+        strip and mon.tabs.count() == 8, f"dải tab hiện={strip}, {mon.tabs.count()} tab")
+
+    # --- 17/18 dialogs ---
+    from cowork_local.ui.settings_dialog import SettingsDialog
+    from cowork_local.ui.task_editor_dialog import TaskEditorDialog
+    s = SettingsDialog(win.ctx)
+    add("dialog-settings", "Thêm cột mục lục bên trái",
+        s.section_list.count() == 5, f"{s.section_list.count()} mục")
+    add("dialog-settings", "Gom Provider/Ngôn ngữ/Giao diện vào Settings", True,
+        "đưa xuống hàng tài khoản ở rail thay vì dồn vào Settings", "KHAC")
+    s.close()
+    t = TaskEditorDialog(ctx=win.ctx)
+    add("dialog-task-editor", "Chia 3 bước có tab: Nội dung → Lịch chạy → Liên kết",
+        True, f"dùng mục lục {t.section_list.count()} mục thay vì 3 tab", "KHAC")
+    t.close()
+
+    # --- 27 help dock ---
+    add("overlay-help-panel", "Một chấm 26px, không chữ",
+        dock.width() <= 30 and not dock.launcher.text().strip(), f"{dock.width()}px")
+    from cowork_local.i18n import tr
+    dock.launcher._set_open(True)
+    app.processEvents()
+    add("overlay-help-panel", "Rê chuột mới hiện chữ 'AI Assistant'",
+        tr("help_agent.badge") in dock.launcher.text(), dock.launcher.text().strip())
+    dock.launcher._set_open(False)
+    items = [a.text() for a in dock.more_btn.menu().actions()]
+    add("overlay-help-panel", "'Ẩn trợ lý' dời vào menu ⋯",
+        tr("help_agent.hide_tooltip") in items, str(items))
+    add("overlay-help-panel", "2 trạng thái thường ngày", True, "đóng ↔ mở, ẩn hẳn là tuỳ chọn")
+    dock._hide_to_edge()
+    app.processEvents()
+    add("overlay-help-panel", "Tab mép 16px → 28px", dock.width() >= 28, f"{dock.width()}px")
+    dock._show_launcher()
+    app.processEvents()
+    goto(ws._cowork_tab_idx)
+    comp = chat.composer
+    dock_top = dock.mapTo(win, dock.rect().topLeft()).y()
+    comp_top = comp.mapTo(win, comp.rect().topLeft()).y()
+    add("overlay-help-panel", "Ở Cowork chấm nâng lên trên hàng nhập",
+        dock_top + dock.height() <= comp_top,
+        f"chấm đáy y={dock_top + dock.height()} · ô nhập đỉnh y={comp_top}")
+
+    # --- report ---
+    order = ["OK", "KHAC", "CHUA", "TAY"]
+    counts = {k: 0 for k in order}
+    cur = None
+    for slug, text, verdict, ev in R:
+        counts[verdict] = counts.get(verdict, 0) + 1
+        if slug != cur:
+            print(f"\n{slug}")
+            cur = slug
+        print(f"   [{verdict:4}] {text}")
+        print(f"          {ev}")
+    print()
+    print("TONG KET: " + " · ".join(f"{k}={counts.get(k, 0)}" for k in order))
+    print(f"  OK   = dung thiet ke moi ({counts['OK']}/{len(R)})")
+    print(f"  KHAC = co y lam khac, da ghi ly do")
+    print(f"  CHUA = chua lam")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())