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/retryable.go

@@ -0,0 +1,51 @@
+package dbsync
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+// RetryableError 上游 IO / remote 暂不可达，agent 可稍后重试（不换 UUID）。
+type RetryableError struct {
+	Msg string
+}
+
+func (e *RetryableError) Error() string {
+	if e == nil {
+		return "retryable error"
+	}
+	return e.Msg
+}
+
+func Retryable(msg string) error {
+	return &RetryableError{Msg: msg}
+}
+
+func Retryablef(format string, args ...any) error {
+	return &RetryableError{Msg: fmt.Sprintf(format, args...)}
+}
+
+func IsRetryable(err error) bool {
+	var r *RetryableError
+	return errors.As(err, &r)
+}
+
+func wrapOpenRemote(err error) error {
+	if err == nil {
+		return nil
+	}
+	msg := err.Error()
+	lower := strings.ToLower(msg)
+	if strings.Contains(lower, "open remote") ||
+		strings.Contains(lower, "unable to open") ||
+		strings.Contains(lower, "no such file") ||
+		strings.Contains(lower, "locked") ||
+		strings.Contains(lower, "busy") ||
+		strings.Contains(lower, "connection refused") ||
+		strings.Contains(lower, "timeout") ||
+		strings.Contains(lower, "i/o") {
+		return Retryablef("open remote: %v", err)
+	}
+	return Retryablef("open remote: %v", err)
+}