Add dropper location selector: discover available droppers on network, pass through server, and add dropdown in order panel for location-based dispensing

web/server/server.js

@@ -169,6 +169,23 @@ app.get('/api/texture/:namespace/*', async (req, res) => {
   }
 });
 
+// Clear negative texture cache (.miss files) — call after updating texture mappings
+app.delete('/api/texture-cache/negative', (req, res) => {
+  let cleared = 0;
+  function walk(dir) {
+    try {
+      for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
+        const full = path.join(dir, entry.name);
+        if (entry.isDirectory()) walk(full);
+        else if (entry.name.endsWith('.miss')) { fs.unlinkSync(full); cleared++; }
+      }
+    } catch (_) { /* ignore */ }
+  }
+  walk(TEXTURE_CACHE_DIR);
+  console.log(`[Texture Cache] Cleared ${cleared} negative cache entries`);
+  res.json({ cleared });
+});
+
 // Health check
 app.get('/api/health', (req, res) => {
   res.json({