Per-product anchors support when using product switcher

[akegaviar]

Description

Currently, navigation.global.anchors applies to all products in a multi-product docs setup. It would be useful to have per-product anchor configuration, allowing different sidebar anchors for each product.

Use case

We have two products (Console and Self-Hosted) and using the Mintlify products switcher. Console needs anchors for Status, Discord, Telegram, Blog, llms.txt, and llms-full.txt. Self-Hosted only needs Discord and Telegram. Currently, both products show the same global anchors.

[akegaviar]

cc @redikultsevsilver