[CI] Initial issue-triage with AI

[Gusarich]

Something like https://github.com/openai/codex has for their CI:

• Labeler https://github.com/openai/codex/blob/main/.github/workflows/issue-labeler.yml
• Deduplicator https://github.com/openai/codex/blob/main/.github/workflows/issue-deduplicator.yml

In context of docs, agent could also look if the issue is actually valid and if it's relevant. - this one should probably be filtered to only be checked for non-maintainer issues.