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/assets/css/layout.css

@@ -0,0 +1,53 @@
+/* ==========================================================================
+   Tiling Window Manager Grids & Layout (layout.css)
+   ========================================================================== */
+
+/* Outer Shell Container */
+.tiling-layout {
+  width: 100%;
+  max-width: var(--site-max-width);
+  display: flex;
+  flex-direction: column;
+  gap: var(--tile-gap);
+}
+
+/* Asymmetric 2-Column Split Grid (Lander: Lead Article + Telemetry Sidebar) */
+.split-grid {
+  display: grid;
+  grid-template-columns: 1.25fr 0.75fr;
+  gap: var(--tile-gap);
+  align-items: start;
+}
+
+@media (max-width: 880px) {
+  .split-grid {
+    grid-template-columns: 1fr;
+  }
+}
+
+/* Article Workspace Grid (Left Sidebar TOC + Main Reading Workspace) */
+.article-workspace-grid {
+  display: grid;
+  grid-template-columns: 290px 1fr;
+  gap: var(--tile-gap);
+  align-items: start;
+}
+
+@media (max-width: 960px) {
+  .article-workspace-grid {
+    grid-template-columns: 1fr;
+  }
+}
+
+/* Generic Symmetrical Grids */
+.grid-2col {
+  display: grid;
+  grid-template-columns: repeat(2, 1fr);
+  gap: var(--tile-gap);
+}
+
+@media (max-width: 768px) {
+  .grid-2col {
+    grid-template-columns: 1fr;
+  }
+}