Update build and install instructions for toolchain-v8 related changes

[mattkjames7]

Release note

Changes to the build instructions and download links due to changes with the new toolchain.

Related product PRs

PRs from product repo this doc page is related to:
memgraph/memgraph#3587

Checklist:

• Add appropriate milestone (current release cycle)
• Add bugfix or feature label, based on the product PR type you're documenting
• Make sure all relevant tech details are documented
  • Update reference pages (e.g. clauses, functions, flags, experimental, monitoring, Cypher differences)
  • Search for the feature you are working on (mentions) and make updates if needed
  • Provide a basic example of usage
  • In case your feature is an Enterprise one, list it under ME page and mark its page with Enterprise (example).
• Check all content with Grammarly
• Perform a self-review of my code
• The build passes locally
• My changes generate no new warnings or errors

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Project	Deployment	Actions	Updated (UTC)
documentation	Ready	Preview	Aug 17, 2026 4:19pm

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