This commit clarifies the purpose of certain environment variables
by explicitly associating them with token management. The variables
PIXIVFE_MAX_RETRIES, PIXIVFE_BASE_TIMEOUT, and PIXIVFE_MAX_BACKOFF_TIME
are now prefixed with "TOKEN_" to better distinguish them from API-level
settings.
The ServerConfig struct, configuration loading, logging,
and documentation have been updated accordingly.
Implement new backoff settings for API requests, distinct from token
management backoff.
Update config, core request handling, and documentation to reflect the
new API request backoff mechanism. Refactor TokenManager to use the
manager's baseTimeout instead of individual token timeouts.
perennial
iacore
VnPower