v1.8.53: fix Redis and MariaDB GUI tabs — wrong client API calls

- redis_tab: fix RedisClient constructor (pass server dict, not alias+store)
- redis_tab: add connect() call, add disconnect on server switch
- redis_tab: remove non-existent db= parameter from execute(), use select_db()
- redis_client: add select_db() method for runtime DB switching
- query_tab: fix use_database() → switch_database(), close() → disconnect()
- query_tab: fix execute() → execute_query() with dict unpacking
- query_tab: add missing connect() call after SQLClient creation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

gui/tabs/query_tab.py

@@ -173,6 +173,9 @@ class QueryTab(ctk.CTkFrame):
                 return
 
             client = SQLClient(server)
+            if not client.connect():
+                self._schedule(self._set_status, t("query_error") + ": connection failed", error=True)
+                return
             databases = client.list_databases()
 
             def _update():
@@ -198,7 +201,7 @@ class QueryTab(ctk.CTkFrame):
         if not self._client:
             return
         try:
-            self._client.use_database(db_name)
+            self._client.switch_database(db_name)
             self._set_status(f"Database: {db_name}")
         except Exception as exc:
             self._set_status(str(exc), error=True)
@@ -206,7 +209,7 @@ class QueryTab(ctk.CTkFrame):
     def _disconnect(self):
         if self._client:
             try:
-                self._client.close()
+                self._client.disconnect()
             except Exception:
                 pass
             self._client = None
@@ -236,7 +239,9 @@ class QueryTab(ctk.CTkFrame):
         """Background thread: execute SQL, measure time, post results."""
         start = time.perf_counter()
         try:
-            columns, rows = self._client.execute(sql)
+            result = self._client.execute_query(sql)
+            columns = result["columns"]
+            rows = result["rows"]
             elapsed = time.perf_counter() - start
 
             def _update():