feat(registry): add avatar promo and Slack notification templates - #3279

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Fetching and validating config file...
Fetching .mintignore file...
Fetching ASSISTANT.md file...
Discovering assistant skills...
Successfully validated docs.json
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DocsConfig evaluation complete
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No SDK reference pages configured
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Successfully updated API reference metadata.
No stale files found
Updating targeted paths:
  catalog/blocks/slack-notification-ad.mdx
Successfully updated deployment
LaTeX configuring is unchanged
Successfully saved config
No stale tracked assets found
Updating navigation...
Navigation updated
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Starting page revalidation...
Revalidating targeted pages...
Revalidating 1 paths
Page revalidation complete
Queued update of llms-full.txt
Skipping revalidation
Updated deployment cache
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Skipped post-activation update of llms-full.txt