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/pool.go

@@ -0,0 +1,85 @@
+package dbsync
+
+import (
+	"database/sql"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+)
+
+// remotePool 复用线上 A 连接，避免每次 push 冷开 SQLite（Windows 上常 >3s → 旧默认超时 503）。
+type remotePool struct {
+	mu  sync.Mutex
+	dbs map[string]*pooledDB
+}
+
+type pooledDB struct {
+	db       *sql.DB
+	driver   Driver
+	lastUsed time.Time
+}
+
+var sharedRemotePool = &remotePool{dbs: map[string]*pooledDB{}}
+
+func poolKey(driver Driver, dsn string) string {
+	if driver == DriverSQLite {
+		dsn = normalizeSQLiteDSN(dsn)
+	}
+	return string(driver) + "|" + dsn
+}
+
+// AcquireRemote 获取（或新建）remote 连接；调用方不要 Close。
+func AcquireRemote(driver Driver, dsn string) (*sql.DB, error) {
+	return sharedRemotePool.acquire(driver, dsn)
+}
+
+func (p *remotePool) acquire(driver Driver, dsn string) (*sql.DB, error) {
+	key := poolKey(driver, dsn)
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	if e, ok := p.dbs[key]; ok && e.db != nil {
+		if err := e.db.Ping(); err == nil {
+			e.lastUsed = time.Now()
+			return e.db, nil
+		}
+		_ = e.db.Close()
+		delete(p.dbs, key)
+	}
+	db, err := Open(driver, dsn)
+	if err != nil {
+		return nil, err
+	}
+	p.dbs[key] = &pooledDB{db: db, driver: driver, lastUsed: time.Now()}
+	return db, nil
+}
+
+// WarmRemote 通道启动时预热，把冷开成本挪出请求路径。
+func WarmRemote(driver Driver, dsn string) error {
+	if strings.TrimSpace(dsn) == "" {
+		return fmt.Errorf("dsn required")
+	}
+	_, err := AcquireRemote(driver, dsn)
+	return err
+}
+
+// InvalidateRemote 通道 DSN 变更或停用时丢掉缓存连接。
+func InvalidateRemote(driver Driver, dsn string) {
+	key := poolKey(driver, dsn)
+	sharedRemotePool.mu.Lock()
+	defer sharedRemotePool.mu.Unlock()
+	if e, ok := sharedRemotePool.dbs[key]; ok {
+		_ = e.db.Close()
+		delete(sharedRemotePool.dbs, key)
+	}
+}
+
+// CloseAllRemotes 测试或进程退出时关闭池内连接。
+func CloseAllRemotes() {
+	sharedRemotePool.mu.Lock()
+	defer sharedRemotePool.mu.Unlock()
+	for k, e := range sharedRemotePool.dbs {
+		_ = e.db.Close()
+		delete(sharedRemotePool.dbs, k)
+	}
+}