feat: tutorials coverage matrix with deep links and collapsible sections

docs/tutorials/index.mdx

@@ -4,6 +4,7 @@ copyright: This file is part of midnight-docs. Copyright (C) Midnight Foundation
 title: Tutorials
 description: Step-by-step tutorials for building DApps on Midnight Network, from your first Compact contract to a full-stack deployment with wallet integration.
 sidebar_position: 4
+hide_table_of_contents: true
 tags:
   - tutorials
   - dapps
@@ -13,6 +14,8 @@ tags:
 ---
 
 import PersonaTiles from '@site/src/components/PersonaTiles';
+import CoverageMatrix from '@site/src/components/CoverageMatrix';
+import { columns as tutorialColumns, features as tutorialFeatures } from '@site/src/components/CoverageMatrix/tutorialsData';
 
 # Tutorials
 
@@ -50,3 +53,30 @@ Step-by-step tutorials for building DApps on Midnight Network. Start with the en
     cta: "Build ZK Loan",
   },
 ]} />
+
+## What each tutorial covers
+
+Each tutorial teaches a different slice of the Midnight stack. Pick a feature or
+pattern from the dropdown to see which tutorials teach it, or expand a section
+to compare tutorials row by row. A filled dot means the tutorial teaches the
+feature in depth, an outlined dot means the feature appears only briefly, and an
+empty cell means the tutorial does not cover it. Every dot links to the section
+of the tutorial where the feature is covered.
+
+<CoverageMatrix
+  columns={tutorialColumns}
+  features={tutorialFeatures}
+  itemNoun="tutorial"
+  fullLabel="Taught in depth"
+  partialLabel="Touched briefly"
+  summaryLabel="Taught by"
+  stretch
+/>
+
+:::note
+
+This matrix covers the written tutorials. Coverage data lives in
+`src/components/CoverageMatrix/tutorialsData.jsx`. When a tutorial is added or
+substantially updated, update the matrix there too.
+
+:::