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

[jocelynlin-wd]

Summary

• 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 since everything is now on Node 20
• Exclude @flowiseai/agentflow and @flowiseai/observe from Docker build — these UI-only SDK packages are not needed for the app runtime, saving ~40–50s per Docker build

FLOWISE-619

Test plan

• Verify CI passes with Node 20.20.2
• Verify Docker image builds successfully with the filtered build command

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request updates the Node.js version to 20.20.2 and modifies the Docker build process to exclude specific UI packages. Feedback suggests that the pnpm build command in the Dockerfile requires a double-dash separator to correctly pass filters to Turbo. Additionally, it is recommended to update the engine constraints in workspace packages, such as the server package, to maintain consistency with the root configuration.

[jocelynlin-wd]

/gemini review

[gemini-code-assist]

Code Review

This pull request updates the Node.js version to 20.20.2 in .nvmrc and restricts the engine requirement to Node 20 in the package configuration files. Additionally, the Dockerfile build command is modified to exclude specific SDK packages using pnpm filters to optimize the build process. I have no feedback to provide.

[jocelynlin-wd]

/gemini review

[gemini-code-assist]

Code Review

This pull request updates the project's Node.js version to 20.20.2 and introduces a specialized build:docker script that excludes specific SDK packages to optimize the Docker build process. It also simplifies the Node.js engine requirements across the repository. The review feedback suggests relaxing the engine constraint from ^20 to >=20 to ensure compatibility with newer LTS versions, such as Node 22, which improves the developer experience and future-proofs the application.