Homepage announcements: cap at 3, per-post opt-out

[devin-ai-integration]

Summary

Homepage announcements are now driven per news post instead of by a fixed slice: every news post appears by default, and the homepage renders the 3 most recent visible ones (a hidden post is skipped over, not counted against the cap).

Opt a post out in its frontmatter:

+++
title = "…"

[extra]
announcement = false
+++

Template logic (templates/index.html):

{% set_global announcements_shown = 0 %}
{% for news_post in news_section.pages %}
{% if announcements_shown < 3 and news_post.extra.announcement | default(value=true) %}
  … card …
  {% set_global announcements_shown = announcements_shown + 1 %}
{% endif %}
{% endfor %}

All existing news posts except the newest ("BMT 2026 will be held on November 14, 2026") are flagged announcement = false, so the homepage currently shows exactly one card. New posts need no frontmatter change to appear.

Link to Devin session: https://app.devin.ai/sessions/b2cad97fe85e4ad7aa2ed105e43fc39b
Requested by: @alphdelta

[devin-ai-integration]

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