Keep logs for a set number of days

Logs grew forever. A daily prune-logs cron now deletes entries older
than the app setting logs_keep_days (Settings > General, super admin;
default AppData.LogsKeepDays, 90), with an index on logs.created_at.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/types/index.ts

@@ -1117,6 +1117,15 @@ export type HookCallRetentionOverview = {
     max: number;
 };
 
+/**
+ * How long logs are kept (Settings > General, `grab-logs-keep-days.ts`).
+ */
+export type LogRetentionOverview = {
+    keep_days: number;
+    default_days: number;
+    max: number;
+};
+
 /**
  * The install's skill limits (Settings > General, `grab-skill-limits.ts`).
  */
@@ -1911,6 +1920,11 @@ export type PagePropsType = {
      * General settings page).
      */
     hook_call_retention?: HookCallRetentionOverview | null;
+    /**
+     * How many days logs are kept, with the code's default (the General
+     * settings page).
+     */
+    log_retention?: LogRetentionOverview | null;
     /**
      * How long closed chatrooms are kept and how many one place keeps, with
      * the code's defaults (the General settings page).