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/index.njk

@@ -0,0 +1,39 @@
+---
+layout: layouts/base.njk
+title: "River Rooks | Engineering Notes & Systems Architecture"
+---
+
+<!-- 1. Lander Hero Tile with Dynamic Filter Tag Buttons -->
+{% include "partials/hero-tile.njk" %}
+
+<!-- 2. Asymmetric Split Grid: Featured Lead Post (Left) & Telemetry Sidebar (Right) -->
+<div class="split-grid">
+  <div class="split-lead-col">
+    {% include "partials/featured-card.njk" %}
+  </div>
+
+  <div class="split-sidebar-col">
+    {% include "partials/stats-sidebar.njk" %}
+  </div>
+</div>
+
+<!-- 3. Full-Width Chronological Dispatches Feed Tile -->
+<section class="tile" aria-label="Dispatches Feed Catalog">
+  <header class="tile-header">
+    <div class="tile-title">
+      <span class="status-indicator"></span>
+      RECENT DISPATCHES
+    </div>
+    <span class="tile-meta">ORDER: CHRONOLOGICAL DESC &bull; TOTAL: {{ collections.posts.length }}</span>
+  </header>
+
+  <div class="feed-list">
+    {% for post in collections.posts %}
+      {% include "partials/post-card.njk" %}
+    {% else %}
+      <p style="color: var(--text-muted); font-family: var(--font-mono); font-size: 0.85rem; padding: 16px;">
+        No published dispatches found in repository.
+      </p>
+    {% endfor %}
+  </div>
+</section>