fix: verify shadow SQL package ownership

fortucky-algorithm/src/main/resources/db/sqlserver/install-shadow.sql

@@ -6,7 +6,20 @@
 SET NOCOUNT ON;
 SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
 
-IF SCHEMA_ID(N'alg') IS NULL EXEC(N'CREATE SCHEMA alg');
+IF SCHEMA_ID(N'alg') IS NOT NULL
+    THROW 51000, 'FT546 shadow install refused: alg schema already exists', 1;
+
+EXEC(N'CREATE SCHEMA alg');
+GO
+
+CREATE TABLE alg.shadow_package_manifest (
+    package_id varchar(80) NOT NULL CONSTRAINT PK_alg_shadow_package_manifest PRIMARY KEY,
+    package_version varchar(40) NOT NULL,
+    installed_at datetime2 NOT NULL CONSTRAINT DF_alg_shadow_package_manifest_installed_at DEFAULT SYSUTCDATETIME()
+);
+
+INSERT INTO alg.shadow_package_manifest (package_id, package_version)
+VALUES ('FT546WMS_SHADOW_ONLY', '2026-08-12-1');
 GO
 
 IF OBJECT_ID(N'alg.warehouse_policy', N'U') IS NULL