feat: integrate eleventy-plugin-mermaid for diagram support

Adds @kevingimbel/eleventy-plugin-mermaid so mermaid fenced code blocks
render as interactive diagrams in the browser.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

_includes/layouts/base.njk

@@ -543,5 +543,6 @@
       }
     })();
   </script>
+  {% mermaid_js %}
 </body>
 </html>

eleventy.config.js

@@ -1,5 +1,6 @@
 import pluginWebmentions from "@chrisburnell/eleventy-cache-webmentions";
 import pluginRss from "@11ty/eleventy-plugin-rss";
+import pluginMermaid from "@kevingimbel/eleventy-plugin-mermaid";
 import embedEverything from "eleventy-plugin-embed-everything";
 import { eleventyImageTransformPlugin } from "@11ty/eleventy-img";
 import sitemap from "@quasibit/eleventy-plugin-sitemap";
@@ -150,6 +151,9 @@ export default function (eleventyConfig) {
   // Custom feed templates in feed.njk and feed-json.njk use these filters
   eleventyConfig.addPlugin(pluginRss);
 
+  // Mermaid diagram support — renders ```mermaid code blocks as diagrams
+  eleventyConfig.addPlugin(pluginMermaid);
+
   // Post graph — GitHub-style contribution grid for posting frequency
   eleventyConfig.addPlugin(postGraph, {
     sort: "desc",

package-lock.json

@@ -18,6 +18,7 @@
         "@atproto/api": "^0.12.0",
         "@chrisburnell/eleventy-cache-webmentions": "^2.2.7",
         "@fontsource/inter": "^5.2.8",
+        "@kevingimbel/eleventy-plugin-mermaid": "^3.0.1",
         "@quasibit/eleventy-plugin-sitemap": "^2.2.0",
         "@resvg/resvg-js": "^2.6.2",
         "@rknightuk/eleventy-plugin-post-graph": "^1.0.8",
@@ -961,6 +962,15 @@
         "@jridgewell/sourcemap-codec": "^1.4.14"
       }
     },
+    "node_modules/@kevingimbel/eleventy-plugin-mermaid": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/@kevingimbel/eleventy-plugin-mermaid/-/eleventy-plugin-mermaid-3.0.1.tgz",
+      "integrity": "sha512-p++zth8mdVroiZp5vspqU9KCNC81shKRgr2Vf8+3kAbcmJHZU+SFnTthsqwTI+R6R3K79JmCBBScIKWkUyEivA==",
+      "license": "ISC",
+      "dependencies": {
+        "he": "^1.2.0"
+      }
+    },
     "node_modules/@nodelib/fs.scandir": {
       "version": "2.1.5",
       "resolved": "https://registry.npmjs.org/@nodelib/fs.scandir/-/fs.scandir-2.1.5.tgz",
@@ -1709,7 +1719,8 @@
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/@types/linkify-it/-/linkify-it-5.0.0.tgz",
       "integrity": "sha512-sVDA58zAw4eWAffKOaQH5/5j3XeayukzDk+ewSsnv3p4yJEZHCCzMDiZM8e0OUrRvmpGZ85jf4yDHkHsgBNr9Q==",
-      "license": "MIT"
+      "license": "MIT",
+      "peer": true
     },
     "node_modules/@types/markdown-it": {
       "version": "14.1.2",
@@ -1726,7 +1737,8 @@
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/@types/mdurl/-/mdurl-2.0.0.tgz",
       "integrity": "sha512-RGdgjQUZba5p6QEFAVx2OGb8rQDL/cPRG7GiedRzMcJ1tYnUANBncjbSB1NRGwbvjcPeikRABz2nshyPk1bhWg==",
-      "license": "MIT"
+      "license": "MIT",
+      "peer": true
     },
     "node_modules/@types/minimatch": {
       "version": "3.0.5",
@@ -2136,7 +2148,6 @@
         }
       ],
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "baseline-browser-mapping": "^2.9.0",
         "caniuse-lite": "^1.0.30001759",
@@ -3833,7 +3844,6 @@
       "integrity": "sha512-/imKNG4EbWNrVjoNC/1H5/9GFy+tqjGBHCaSsN+P2RnPqjsLmv6UD3Ej+Kj8nBWaRAwyk7kK5ZUc+OEatnTR3A==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "bin": {
         "jiti": "bin/jiti.js"
       }
@@ -4653,7 +4663,6 @@
         }
       ],
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "nanoid": "^3.3.11",
         "picocolors": "^1.1.1",
@@ -4881,7 +4890,6 @@
       "resolved": "https://registry.npmjs.org/posthtml/-/posthtml-0.16.7.tgz",
       "integrity": "sha512-7Hc+IvlQ7hlaIfQFZnxlRl0jnpWq2qwibORBhQYIb0QbNtuicc5ZxvKkVT71HJ4Py1wSZ/3VR1r8LfkCtoCzhw==",
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "posthtml-parser": "^0.11.0",
         "posthtml-render": "^3.0.0"
@@ -5850,7 +5858,6 @@
       "integrity": "sha512-3ofp+LL8E+pK/JuPLPggVAIaEuhvIz4qNcf3nA1Xn2o/7fb7s/TYpHhwGDv1ZU3PkBluUVaF8PyCHcm48cKLWQ==",
       "dev": true,
       "license": "MIT",
-      "peer": true,
       "dependencies": {
         "@alloc/quick-lru": "^5.2.0",
         "arg": "^5.0.2",

package.json

@@ -21,6 +21,7 @@
     "@atproto/api": "^0.12.0",
     "@chrisburnell/eleventy-cache-webmentions": "^2.2.7",
     "@fontsource/inter": "^5.2.8",
+    "@kevingimbel/eleventy-plugin-mermaid": "^3.0.1",
     "@quasibit/eleventy-plugin-sitemap": "^2.2.0",
     "@resvg/resvg-js": "^2.6.2",
     "@rknightuk/eleventy-plugin-post-graph": "^1.0.8",