feat: harden loose-offline sync for user JWT, schema, and console ops

Enable Binding-scoped agent push/pull, empty-table schema ensure, SyncPage inspect/drop-table, default module import, and agent-bound publish docs from the 宇恒联调意见.

Co-authored-by: Cursor <cursoragent@cursor.com>

platform/internal/dbsync/manager.go

@@ -55,6 +55,12 @@ func (m *Manager) StartChannel(id string) error {
 		c.Enabled = true
 		c.LastError = ""
 	})
+	// 预热 remote，避免首个 agent push 冷开 SQLite 触发超时
+	go func(driver Driver, dsn string) {
+		if err := WarmRemote(driver, dsn); err != nil {
+			log.Printf("dbsync warm remote %s: %v", id, err)
+		}
+	}(ch.Remote.Driver, ch.Remote.DSN)
 	return nil
 }
 
@@ -65,6 +71,9 @@ func (m *Manager) StopChannel(id string) {
 		cancel()
 		delete(m.runners, id)
 	}
+	if ch, err := m.store.GetChannel(id); err == nil {
+		InvalidateRemote(ch.Remote.Driver, ch.Remote.DSN)
+	}
 	_ = m.store.PatchStats(id, func(c *Channel) { c.Enabled = false })
 }