feat: ship loose-offline dbsync (validate, agent push, LWW audit)

Add UUID/FK channel checks, agent whitelist/push APIs, bindings, super-admin LWW audit with rollback, reconcile rate limits, and sync docs. Default customers stay opt-in; company conflict UI is removed.

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

platform/internal/config/config.go

@@ -68,6 +68,8 @@ type StorageConf struct {
 }
 
 type DBSyncConf struct {
-	Enabled bool   `json:",default=true"`
-	DataDir string `json:",default=./data/dbsync"` // 通道/冲突队列 JSON
+	Enabled            bool `json:",default=true"`
+	DataDir            string `json:",default=./data/dbsync"` // 通道/冲突/LWW 审计 JSON
+	LwwAuditTTLDays    int  `json:",default=90"`             // 超管 LWW 覆盖日志保留天数
+	ReconcileMinSec    int  `json:",default=300"`            // 手动对账最小间隔（秒）
 }