feat(routing): ô định tuyến chỉ còn Auto và Manual

Bỏ hai chế độ Off và Fallback ở ô định tuyến cạnh khung chat và ở mục Định
tuyến trong Cài đặt. Mặc định chuyển sang Auto.

- USER_ROUTING_MODES = ("auto", "manual"); giá trị off/fallback/lạ còn lưu trong
  config hay project đều được hiểu là Auto (routing_mode_for,
  project_routing_mode, set_*). Engine vẫn hiểu "off" khi truyền mode_override
  tường minh.
- RoutingScheduler: định tuyến giờ luôn bật nên việc chấm điểm model định kỳ
  luôn chạy; muốn tắt thì đặt reassess_interval_hours = 0.
- Cập nhật các test đang ghim hành vi "mặc định off".

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/routing/test_per_workspace_modes.py

@@ -32,16 +32,29 @@ def _mk(ctx, name):
 def test_defaults_follow_global_when_no_override(ctx):
     a = _mk(ctx, "Alpha")
     ctx.active_project_id = a.project_id
-    # Global default switch_mode is "off".
-    assert ctx.project_routing_mode("cowork") == "off"
+    # Global default switch_mode is "auto" (Off was removed).
+    assert ctx.project_routing_mode("cowork") == "auto"
     # Change the GLOBAL default → project with no override follows it.
-    ctx.config.data["routing"]["switch_mode"] = "auto"
+    ctx.config.data["routing"]["switch_mode"] = "manual"
+    assert ctx.project_routing_mode("cowork") == "manual"
+
+
+def test_legacy_off_and_fallback_resolve_to_auto(ctx):
+    a = _mk(ctx, "Alpha")
+    ctx.active_project_id = a.project_id
+    ctx.config.data["routing"]["switch_mode"] = "manual"
+    for legacy in ("off", "fallback"):
+        a.routing_modes = {"cowork": legacy}
+        save_project(a)
+        assert ctx.project_routing_mode("cowork") == "auto"
+    ctx.set_project_routing_mode("cowork", "off")
     assert ctx.project_routing_mode("cowork") == "auto"
 
 
 def test_per_workspace_routing_is_isolated(ctx):
     a = _mk(ctx, "Alpha")
     b = _mk(ctx, "Beta")
+    ctx.config.data["routing"]["switch_mode"] = "manual"
 
     ctx.active_project_id = a.project_id
     ctx.set_project_routing_mode("cowork", "auto")
@@ -49,16 +62,19 @@ def test_per_workspace_routing_is_isolated(ctx):
 
     # Switching to workspace B must NOT see A's override (falls back to global).
     ctx.active_project_id = b.project_id
-    assert ctx.project_routing_mode("cowork") == "off"
-
-    # B sets its own, independently.
-    ctx.set_project_routing_mode("cowork", "manual")
     assert ctx.project_routing_mode("cowork") == "manual"
 
-    # A is unchanged.
+    # B sets its own, independently.
+    ctx.set_project_routing_mode("cowork", "auto")
     ctx.active_project_id = a.project_id
+    ctx.set_project_routing_mode("cowork", "manual")
+    ctx.active_project_id = b.project_id
     assert ctx.project_routing_mode("cowork") == "auto"
 
+    # A keeps its own.
+    ctx.active_project_id = a.project_id
+    assert ctx.project_routing_mode("cowork") == "manual"
+
 
 def test_per_surface_isolated_within_a_workspace(ctx):
     a = _mk(ctx, "Alpha")
@@ -68,7 +84,8 @@ def test_per_surface_isolated_within_a_workspace(ctx):
     # co4e untouched → global default.
     assert ctx.project_routing_mode("cowork") == "auto"
     assert ctx.project_routing_mode("ai_edit") == "manual"
-    assert ctx.project_routing_mode("co4e") == "off"
+    ctx.config.data["routing"]["switch_mode"] = "manual"
+    assert ctx.project_routing_mode("co4e") == "manual"
 
 
 def test_routing_mode_persists_to_disk(ctx):

tests/routing/test_service.py

@@ -88,12 +88,21 @@ def test_best_for_returns_strong(service):
     assert ranking.best.assessment.metadata.model_id == "strong-model"
 
 
-def test_route_off_never_switches(service):
+def test_route_off_explicit_override_never_switches(service):
+    # "off" is no longer user-selectable, but the engine still honours it
+    # when passed explicitly.
+    service.reassess()
+    r = service.route("cowork", "Write a Python function", "anthropic", "weak-model",
+                      mode_override="off")
+    assert r.mode == SwitchMode.OFF
+    assert r.should_switch is False
+
+
+def test_legacy_off_in_config_routes_as_auto(service):
     service.reassess()
     service.ctx.config.data["routing"]["switch_mode"] = "off"
     r = service.route("cowork", "Write a Python function", "anthropic", "weak-model")
-    assert r.mode == SwitchMode.OFF
-    assert r.should_switch is False
+    assert r.mode == SwitchMode.AUTO
 
 
 def test_route_auto_switches_to_strong(service):
@@ -147,12 +156,12 @@ def test_route_never_raises_on_broken_store(ctx, tmp_path):
 
 def test_per_surface_mode_override(service):
     service.reassess()
-    service.ctx.config.data["routing"]["switch_mode"] = "off"
+    service.ctx.config.data["routing"]["switch_mode"] = "manual"
     service.ctx.config.data["routing"]["surface_modes"]["co4e"] = "auto"
-    # cowork follows global (off); co4e overridden to auto
+    # cowork follows global (manual); co4e overridden to auto
     r_cowork = service.route("cowork", "Write a Python function", "anthropic", "weak-model")
     r_co4e = service.route("co4e", "Write a Python function", "anthropic", "weak-model")
-    assert r_cowork.mode == SwitchMode.OFF
+    assert r_cowork.mode == SwitchMode.MANUAL
     assert r_co4e.mode == SwitchMode.AUTO
     assert r_co4e.should_switch is True