feat: implement dynamic Eleventy tiling blog, modular CSS, and agent customizations

- Add project foundation README.md and root AGENTS.md for pair programming
- Configure .agents/ rules and skills for Eleventy tiling and Obsidian publishing
- Decompose monolithic styles into modular tokens, reset, layout, and component CSS
- Implement Nunjucks layout inheritance (base.njk, post.njk, page.njk) and reusable partials
- Configure Eleventy 3 with markdown-it-anchor, syntax highlighting, and dynamic collections
- Migrate sample prototypes into dynamic dispatches lander, gateway, and Markdown posts
- Add multi-stage Dockerfile and clean-URL nginx.conf for production serving

src/_includes/macros/tile.njk

@@ -0,0 +1,30 @@
+{# 
+  Reusable Tile Container Macro (macros/tile.njk)
+  Renders a terminal pane with header, title, meta pill, and custom body slot.
+  Usage:
+    {% import "macros/tile.njk" as ui %}
+    {% call ui.tile(title="STATISTICS", meta="STATIC HTML") %}
+      <p>Inside tile</p>
+    {% endcall %}
+#}
+
+{% macro tile(title="", meta="", class="", id="") %}
+<section class="tile {{ class }}" {% if id %}id="{{ id }}"{% endif %}>
+  {% if title or meta %}
+  <header class="tile-header">
+    {% if title %}
+    <div class="tile-title">
+      <span class="status-indicator"></span>
+      {{ title }}
+    </div>
+    {% endif %}
+    {% if meta %}
+    <span class="tile-meta">{{ meta }}</span>
+    {% endif %}
+  </header>
+  {% endif %}
+  <div class="tile-content">
+    {{ caller() }}
+  </div>
+</section>
+{% endmacro %}