feat: add configurable retention period for Redis usage queue

- Introduced `redis-usage-queue-retention-seconds` config parameter with a default of 60 seconds and a max of 3600 seconds.
- Updated logic in `redisqueue` to honor configurable retention periods for enqueued usage data.
- Modified config validation and initialization to support and enforce retention limits.
- Enhanced change tracking in `config_diff` to detect updates to this parameter.

config.example.yaml

@@ -66,6 +66,10 @@ error-logs-max-files: 10
 # When false, disable in-memory usage statistics aggregation
 usage-statistics-enabled: false
 
+# How long (in seconds) Redis usage queue items are retained in memory for the RESP interface (LPOP/RPOP).
+# Default: 60. Max: 3600.
+redis-usage-queue-retention-seconds: 60
+
 # Proxy URL. Supports socks5/http/https protocols. Example: socks5://user:pass@192.168.1.1:1080/
 # Per-entry proxy-url also supports "direct" or "none" to bypass both the global proxy-url and environment proxies explicitly.
 proxy-url: ""