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/drop_table_test.go

@@ -0,0 +1,56 @@
+package dbsync
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+)
+
+func TestDropTableOnEndpoint(t *testing.T) {
+	dir := t.TempDir()
+	dsn := "file:" + filepath.ToSlash(filepath.Join(dir, "drop.db")) + "?_pragma=busy_timeout(5000)"
+	db, err := Open(DriverSQLite, dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx := context.Background()
+	if err := EnsureTableFromColumns(ctx, db, DriverSQLite, "模块·测2·item", "id", []string{"id", "before_day"}); err != nil {
+		t.Fatal(err)
+	}
+	if err := EnsureMeta(ctx, db, DriverSQLite); err != nil {
+		t.Fatal(err)
+	}
+	_ = UpsertMeta(ctx, db, DriverSQLite, "模块·测2·item", "pk1", 1)
+	_ = db.Close()
+
+	ep := Endpoint{Driver: DriverSQLite, DSN: dsn}
+	res, err := DropTableOnEndpoint(ctx, ep, "remote", "模块·测2·item")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !res.OK || !res.Dropped {
+		t.Fatalf("unexpected: %+v", res)
+	}
+	if res.MetaCleared < 1 {
+		t.Fatalf("want meta cleared: %+v", res)
+	}
+
+	db2, err := Open(DriverSQLite, dsn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db2.Close()
+	exists, err := tableExists(ctx, db2, DriverSQLite, "模块·测2·item")
+	if err != nil || exists {
+		t.Fatalf("table should be gone exists=%v err=%v", exists, err)
+	}
+
+	// idempotent
+	res2, err := DropTableOnEndpoint(ctx, ep, "remote", "模块·测2·item")
+	if err != nil || !res2.OK || res2.Dropped {
+		t.Fatalf("idempotent: %+v err=%v", res2, err)
+	}
+	if _, err := DropTableOnEndpoint(ctx, ep, "remote", "_ajz_sync_meta"); err == nil {
+		t.Fatal("expected reject system table")
+	}
+}