feat: 增加 SafeW 已监控群列表接口

通过 getUpdates 将群写入 Redis，供创建/编辑渠道时选择 chat_id，避免前端重复传递 token。

internal/safew/watcher.go

@@ -0,0 +1,117 @@
+package safew
+
+import (
+	"context"
+	"log/slog"
+	"sync"
+	"time"
+
+	"aiaa-notification-service/internal/adapter"
+)
+
+type Poller func(token string, offset int64, timeout int) ([]adapter.SafewChat, int64, error)
+
+type Watcher struct {
+	store  ChatStore
+	poll   Poller
+	bgIdle time.Duration
+
+	mu      sync.Mutex
+	running map[string]context.CancelFunc
+	stopped bool
+}
+
+func NewWatcher(store ChatStore, poll Poller) *Watcher {
+	return &Watcher{
+		store:   store,
+		poll:    poll,
+		bgIdle:  time.Second,
+		running: map[string]context.CancelFunc{},
+	}
+}
+
+func (w *Watcher) Ensure(token string) {
+	if token == "" || w == nil {
+		return
+	}
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	if w.stopped {
+		return
+	}
+	if _, ok := w.running[token]; ok {
+		return
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	w.running[token] = cancel
+	go w.loop(ctx, token)
+}
+
+func (w *Watcher) Stop() {
+	w.mu.Lock()
+	w.stopped = true
+	for _, cancel := range w.running {
+		cancel()
+	}
+	w.running = map[string]context.CancelFunc{}
+	w.mu.Unlock()
+}
+
+func (w *Watcher) Refresh(ctx context.Context, token string) error {
+	return w.pollOnce(ctx, token, 0)
+}
+
+func (w *Watcher) List(ctx context.Context, token, q string) ([]adapter.SafewChat, error) {
+	chats, err := w.store.ListSafewChats(ctx, token)
+	if err != nil {
+		return nil, err
+	}
+	return adapter.FilterSafewChats(chats, q), nil
+}
+
+func (w *Watcher) loop(ctx context.Context, token string) {
+	for {
+		if err := w.pollOnce(ctx, token, 30); err != nil {
+			if ctx.Err() != nil {
+				return
+			}
+			slog.Warn("safew watcher poll", "error", err)
+		}
+		idle := w.bgIdle
+		if idle <= 0 {
+			idle = time.Second
+		}
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(idle):
+		}
+	}
+}
+
+func (w *Watcher) pollOnce(ctx context.Context, token string, timeout int) error {
+	ok, err := w.store.TrySafewPollLock(ctx, token, 35*time.Second)
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return nil
+	}
+	defer func() { _ = w.store.UnlockSafewPoll(ctx, token) }()
+
+	offset, err := w.store.GetSafewOffset(ctx, token)
+	if err != nil {
+		return err
+	}
+	chats, next, err := w.poll(token, offset, timeout)
+	if err != nil {
+		return err
+	}
+	if err := w.store.MergeSafewChats(ctx, token, chats); err != nil {
+		return err
+	}
+	if next != offset {
+		return w.store.SetSafewOffset(ctx, token, next)
+	}
+	return nil
+}