chore: update Node.js version consistency and optimize Docker build

- Bump .nvmrc from v20.19.2 to v20.20.2 to match CI
- Narrow package.json engines from >=18.15.0 <19.0.0 || ^20 to ^20
- Exclude @flowiseai/agentflow and @flowiseai/observe from Docker build

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: jocelynlin-wd

.nvmrc

@@ -1 +1 @@
-v20.19.2
+v20.20.2

Dockerfile

@@ -30,9 +30,9 @@ WORKDIR /usr/src/flowise
 # Copy app source
 COPY . .
 
-# Install dependencies and build
+# Install dependencies and build (excluding UI-only packages not needed for Docker)
 RUN pnpm install && \
-    pnpm build
+    pnpm build --filter=!@flowiseai/agentflow --filter=!@flowiseai/observe
 
 # Give the node user ownership of the application files
 RUN chown -R node:node .

package.json

@@ -92,7 +92,7 @@
         }
     },
     "engines": {
-        "node": ">=18.15.0 <19.0.0 || ^20",
+        "node": "^20",
         "pnpm": "^10.26.0"
     },
     "resolutions": {