DSH provider-level web search failover pool

Key features

• Provider Level Transparent Replacement: no intrusion to take over DSH ctx.web + grab, keep original web search / Web fetch signature unchanged.
• Real-time key fillingAPI Key (supported by multiple lines) is always filled in or updated, and click saves immediately hot.
• Priority (Fiilover)Try from high to low in order of priority, with the previous back end failing or melting automatically down.
• Weighted RotateSpreading search traffic to all health engines at 110 weights, maximizing the amount of free from all major sources.