feat(p0): add favorite folder sync and sqlite data foundation

Implement P0 of the reaction dashboard: config loading with hot reload, SQLite migrations with backups, single-writer queue, read-only Bilibili fav client, folder import/diff sync, invalid-resource handling, blacklist seed, scheduler, and JSON redacted logging. Includes offline unit and transport-level contract tests; all existing and new tests pass.

tests/test_scheduler.py

@@ -0,0 +1,122 @@
+# -*- coding: utf-8 -*-
+"""内置调度器测试（离线）: uv run python tests/test_scheduler.py"""
+
+import os
+import sys
+import threading
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+sys.stdout.reconfigure(encoding="utf-8")
+
+from reaction_board.scheduler import ScheduledTask, Scheduler  # noqa: E402
+
+
+def test_run_when_due_and_reschedule():
+    clock = [1_000.0]
+    calls = []
+
+    task = ScheduledTask("sync", 60, lambda: calls.append(clock[0]))
+    scheduler = Scheduler([task], clock=lambda: clock[0])
+    assert scheduler.run_due() and len(calls) == 1
+    assert task.next_run == 1_060.0
+
+    clock[0] = 1_059.0
+    assert scheduler.run_due() == []
+    assert len(calls) == 1
+
+    clock[0] = 1_060.0
+    results = scheduler.run_due()
+    assert len(results) == 1
+    assert calls == [1_000.0, 1_060.0]
+    assert task.next_run == 1_120.0
+
+
+def test_task_error_does_not_block_other_tasks():
+    clock = [100.0]
+    calls = []
+
+    def boom():
+        raise RuntimeError("api down")
+
+    scheduler = Scheduler(
+        [
+            ScheduledTask("bad", 10, boom),
+            ScheduledTask("good", 10, lambda: calls.append("ok")),
+        ],
+        clock=lambda: clock[0],
+    )
+    results = scheduler.run_due()
+    assert [r.ok for r in results] == [False, True]
+    assert results[0].error == "api down"
+    assert calls == ["ok"]
+    # 失败任务仍然被重新排期
+    assert all(t.next_run == 110.0 for t in scheduler.tasks)
+
+
+def test_run_forever_with_stop_event():
+    clock = [0.0]
+    calls = []
+
+    def tick():
+        calls.append(clock[0])
+        clock[0] += 10
+
+    stop = threading.Event()
+    scheduler = Scheduler(
+        [ScheduledTask("tick", 10, tick)],
+        clock=lambda: clock[0],
+        sleeper=lambda seconds: None,
+    )
+
+    def stop_soon():
+        while len(calls) < 3:
+            pass
+        stop.set()
+
+    waiter = threading.Thread(target=stop_soon)
+    waiter.start()
+    scheduler.run_forever(stop_event=stop, poll_seconds=0.001)
+    waiter.join(timeout=2)
+    assert len(calls) >= 3
+
+
+def test_max_iterations_and_validation():
+    calls = []
+    tick_clock = [0.0]
+
+    def next_time():
+        tick_clock[0] += 1.0
+        return tick_clock[0]
+
+    scheduler = Scheduler(
+        [ScheduledTask("t", 1, lambda: calls.append(1))],
+        clock=next_time,
+        sleeper=lambda seconds: None,
+    )
+    scheduler.run_forever(max_iterations=2)
+    assert len(calls) == 2
+
+    for tasks, kwargs in [
+        ([], {}),
+        ([ScheduledTask("bad", 0, lambda: None)], {}),
+        ([ScheduledTask("t", 1, lambda: None)], {"poll_seconds": 0}),
+    ]:
+        try:
+            s = Scheduler(tasks, sleeper=lambda seconds: None)
+            s.run_forever(max_iterations=1, **kwargs)
+        except ValueError:
+            pass
+        else:
+            raise AssertionError(f"应当失败: {tasks}, {kwargs}")
+
+
+def main():
+    test_run_when_due_and_reschedule()
+    test_task_error_does_not_block_other_tasks()
+    test_run_forever_with_stop_event()
+    test_max_iterations_and_validation()
+    print("OK: 内置调度器测试全部通过")
+
+
+if __name__ == "__main__":
+    main()