Drop qt_users dependency for configs and track app version

migrations/006_add_local_configuration_versions.sql

@@ -14,6 +14,7 @@ CREATE TABLE local_configuration_versions (
     data TEXT NOT NULL,
     change_note TEXT NULL,
     created_by TEXT NULL,
+    app_version TEXT NULL,
     created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
     FOREIGN KEY (configuration_uuid) REFERENCES local_configurations(uuid),
     UNIQUE(configuration_uuid, version_no)
@@ -36,6 +37,7 @@ INSERT INTO local_configuration_versions (
     data,
     change_note,
     created_by,
+    app_version,
     created_at
 )
 SELECT
@@ -58,10 +60,12 @@ SELECT
         'synced_at', synced_at,
         'sync_status', sync_status,
         'original_user_id', original_user_id,
-        'original_username', original_username
+        'original_username', original_username,
+        'app_version', NULL
     ) AS data,
     'Initial snapshot backfill (v1)' AS change_note,
     NULL AS created_by,
+    NULL AS app_version,
     COALESCE(created_at, CURRENT_TIMESTAMP) AS created_at
 FROM local_configurations;
 

migrations/007_detach_configurations_from_qt_users.sql

@@ -0,0 +1,25 @@
+-- Detach qt_configurations from qt_users (ownership is owner_username text)
+-- Safe for MySQL 8+/MariaDB 10.2+ via INFORMATION_SCHEMA checks.
+
+SET @fk_exists := (
+    SELECT COUNT(*)
+    FROM information_schema.TABLE_CONSTRAINTS
+    WHERE CONSTRAINT_SCHEMA = DATABASE()
+      AND TABLE_NAME = 'qt_configurations'
+      AND CONSTRAINT_NAME = 'fk_qt_configurations_user'
+      AND CONSTRAINT_TYPE = 'FOREIGN KEY'
+);
+
+SET @drop_fk_sql := IF(
+    @fk_exists > 0,
+    'ALTER TABLE qt_configurations DROP FOREIGN KEY fk_qt_configurations_user',
+    'SELECT ''fk_qt_configurations_user not found, skip'' '
+);
+PREPARE stmt_drop_fk FROM @drop_fk_sql;
+EXECUTE stmt_drop_fk;
+DEALLOCATE PREPARE stmt_drop_fk;
+
+-- user_id becomes optional legacy column (can stay NULL)
+ALTER TABLE qt_configurations
+    MODIFY COLUMN user_id BIGINT UNSIGNED NULL;
+

migrations/008_add_app_version_to_configurations.sql

@@ -0,0 +1,4 @@
+-- Track application version used for configuration writes (create/update via sync)
+ALTER TABLE qt_configurations
+    ADD COLUMN app_version VARCHAR(64) NULL DEFAULT NULL AFTER owner_username;
+