feat(site): wire landing to deployed app demo

- All CTAs (nav, hero, install note, gallery, catalog, footer) link to
  https://containr-app.vercel.app - the app frontend deployed as a
  public demo (VITE_PUBLIC_DEMO build).
- templates.html: per-template "Open in demo app" deep links via
  ?template=<id>; dead default API removed so the official snapshot
  renders instantly until an instance is configured with ?api=.
- Hero canvas screenshot updated to the fullscreen canvas build.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

site/templates.json

@@ -6,7 +6,7 @@
       "description": "Generic Node.js application with automatic dependency detection",
       "category": "web",
       "logo": "https://cdn.simpleicons.org/node.js",
-      "config": "{\"type\":\"web\",\"runtime\":\"node\",\"build_command\":\"npm install \u0026\u0026 npm run build\",\"start_command\":\"npm start\",\"port\":3000,\"health_check\":\"/health\"}",
+      "config": "{\"type\":\"web\",\"runtime\":\"node\",\"build_command\":\"npm install && npm run build\",\"start_command\":\"npm start\",\"port\":3000,\"health_check\":\"/health\"}",
       "variables": "[{\"key\":\"NODE_ENV\",\"label\":\"Node Environment\",\"default\":\"production\",\"required\":false,\"secret\":false},{\"key\":\"NPM_TOKEN\",\"label\":\"NPM Token\",\"default\":\"\",\"required\":false,\"secret\":true}]",
       "is_official": true,
       "is_public": false,
@@ -19,7 +19,7 @@
       "description": "React single-page application with Vite",
       "category": "frontend",
       "logo": "https://cdn.simpleicons.org/react",
-      "config": "{\"type\":\"web\",\"runtime\":\"node\",\"build_command\":\"npm install \u0026\u0026 npm run build\",\"start_command\":\"npx serve -s dist\",\"port\":3000}",
+      "config": "{\"type\":\"web\",\"runtime\":\"node\",\"build_command\":\"npm install && npm run build\",\"start_command\":\"npx serve -s dist\",\"port\":3000}",
       "variables": "[{\"key\":\"VITE_API_URL\",\"label\":\"API URL\",\"default\":\"\",\"required\":true,\"secret\":false}]",
       "is_official": true,
       "is_public": false,
@@ -148,7 +148,7 @@
       "name": "Background Worker",
       "description": "Background job processing service",
       "category": "worker",
-      "logo": "https://cdn.simpleicons.org/terminal",
+      "logo": "",
       "config": "{\"type\":\"worker\",\"runtime\":\"node\",\"build_command\":\"npm install\",\"start_command\":\"npm run worker\"}",
       "variables": "[{\"key\":\"WORKER_CONCURRENCY\",\"label\":\"Concurrency\",\"default\":\"4\",\"required\":false,\"secret\":false}]",
       "is_official": true,
@@ -161,7 +161,7 @@
       "name": "Cron Job",
       "description": "Scheduled task runner",
       "category": "cron",
-      "logo": "https://cdn.simpleicons.org/clock",
+      "logo": "",
       "config": "{\"type\":\"cron\",\"runtime\":\"node\",\"build_command\":\"npm install\",\"start_command\":\"npm run cron\"}",
       "variables": "[{\"key\":\"CRON_SCHEDULE\",\"label\":\"Schedule\",\"default\":\"0 * * * *\",\"required\":true,\"secret\":false}]",
       "is_official": true,
@@ -226,7 +226,7 @@
       "name": "Uptime Kuma",
       "description": "Self-hosted monitoring tool for services and websites",
       "category": "app",
-      "logo": "https://cdn.simpleicons.org/uptimerobot",
+      "logo": "https://cdn.simpleicons.org/uptimekuma",
       "config": "{\"type\":\"web\",\"runtime\":\"louislam/uptime-kuma:1\",\"port\":3001,\"health_check\":\"/\"}",
       "variables": "[]",
       "is_official": true,
@@ -391,4 +391,4 @@
       "updated_at": "0001-01-01T00:00:00Z"
     }
   ]
-}
+}