[2.9.0] Rename plugin to compound-engineering

BREAKING: Plugin renamed from compounding-engineering to compound-engineering.
Users will need to reinstall with the new name:

  claude /plugin install compound-engineering

Changes:
- Renamed plugin directory and all references
- Updated documentation counts (24 agents, 19 commands)
- Added julik-frontend-races-reviewer to docs

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

docs/pages/getting-started.html

@@ -103,7 +103,7 @@
           <h3>Step 2: Install the Plugin</h3>
           <p>Now grab the plugin itself:</p>
           <div class="card-code-block">
-            <pre><code>claude /plugin install compounding-engineering</code></pre>
+            <pre><code>claude /plugin install compound-engineering</code></pre>
           </div>
 
           <h3>Step 3: Verify Installation</h3>
@@ -111,7 +111,7 @@
           <div class="card-code-block">
             <pre><code>claude /plugin list</code></pre>
           </div>
-          <p>You'll see <code>compounding-engineering</code> in the list. If you do, you're ready.</p>
+          <p>You'll see <code>compound-engineering</code> in the list. If you do, you're ready.</p>
 
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