fix: wrap createContainer with user-friendly DC-201 error for missing images

dashcaddy-api/routes/apps/deploy.js

@@ -197,8 +197,18 @@ module.exports = function({ docker, caddy, credentialManager, servicesStateManag
         }
       }
 
-      const container = await docker.client.createContainer(containerConfig);
+      let container;
+      try {
+        container = await docker.client.createContainer(containerConfig);
         await container.start();
+      } catch (createErr) {
+        // If create fails with "no such image", wrap with user-friendly message
+        const errMsg = createErr?.message || String(createErr);
+        if (errMsg.includes('No such image') || errMsg.includes('no such image')) {
+          throw new Error(`[DC-201] Image pull succeeded but container creation failed — image may be corrupted: ${processedTemplate.docker.image}. ${errMsg}`);
+        }
+        throw createErr;
+      }
 
       // Prune dangling images to prevent disk bloat
       try {