feat: WordPress plugin versioning + heatmap fix + dynamic latest download

- Add VERSION file (1.5.4) for tracking WP plugin version
- Update plugin headers to 1.5.4 (cannaiq-menus.php, crawlsy-menus.php)
- Add dynamic /downloads/cannaiq-menus-latest.zip route that auto-redirects
  to highest version (no manual symlinks needed)
- Update frontend download links to use -latest.zip
- Fix StateHeatmap.tsx to parse API values as numbers (fixes string concat bug)
- Document versioning rules in CLAUDE.md

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/index.ts

@@ -32,6 +32,37 @@ app.use('/images', express.static(LOCAL_IMAGES_PATH));
 // Serve static downloads (plugin files, etc.)
 // Uses ./public/downloads relative to working directory (works for both Docker and local dev)
 const LOCAL_DOWNLOADS_PATH = process.env.LOCAL_DOWNLOADS_PATH || './public/downloads';
+
+// Dynamic "latest" redirect for WordPress plugin - finds highest version automatically
+app.get('/downloads/cannaiq-menus-latest.zip', (req, res) => {
+  const fs = require('fs');
+  const path = require('path');
+  try {
+    const files = fs.readdirSync(LOCAL_DOWNLOADS_PATH);
+    const pluginFiles = files
+      .filter((f: string) => f.match(/^cannaiq-menus-\d+\.\d+\.\d+\.zip$/))
+      .sort((a: string, b: string) => {
+        const vA = a.match(/(\d+)\.(\d+)\.(\d+)/);
+        const vB = b.match(/(\d+)\.(\d+)\.(\d+)/);
+        if (!vA || !vB) return 0;
+        for (let i = 1; i <= 3; i++) {
+          const diff = parseInt(vB[i]) - parseInt(vA[i]);
+          if (diff !== 0) return diff;
+        }
+        return 0;
+      });
+
+    if (pluginFiles.length > 0) {
+      const latestFile = pluginFiles[0];
+      res.redirect(302, `/downloads/${latestFile}`);
+    } else {
+      res.status(404).json({ error: 'No plugin versions found' });
+    }
+  } catch (err) {
+    res.status(500).json({ error: 'Failed to find latest plugin' });
+  }
+});
+
 app.use('/downloads', express.static(LOCAL_DOWNLOADS_PATH));
 
 // Simple health check for load balancers/K8s probes