feat: add personal chat model overrides (#24715)

coderd/database/queries/users.sql

@@ -240,6 +240,23 @@ END
 WHERE user_configs.user_id = @user_id
 	AND user_configs.key = 'chat_debug_logging_enabled';
 
+-- name: ListUserChatPersonalModelOverrides :many
+SELECT key, value FROM user_configs
+WHERE user_id = @user_id
+	AND key LIKE 'chat\_personal\_model\_override:%'
+ORDER BY key;
+
+-- name: GetUserChatPersonalModelOverride :one
+SELECT value AS personal_model_override FROM user_configs
+WHERE user_id = @user_id
+	AND key = @key;
+
+-- name: UpsertUserChatPersonalModelOverride :exec
+INSERT INTO user_configs (user_id, key, value)
+VALUES (@user_id::uuid, @key::text, @value::text)
+ON CONFLICT ON CONSTRAINT user_configs_pkey
+DO UPDATE SET value = @value::text;
+
 -- name: GetUserTaskNotificationAlertDismissed :one
 SELECT
 	value::boolean as task_notification_alert_dismissed