ci: split test workflows

[longlho]

Summary

• split the combined test workflow into npm and native CLI workflows
• keep the npm workflow focused on N-API package builds and package smoke tests
• keep the native workflow focused on Bazel/Rust tests plus native CLI binary smoke tests
• remove redundant workflow-level compilation_mode flags now that release targets set opt through with_cfg

Test Plan

• git diff --check
• ruby -e 'require "yaml"; ARGV.each { |f| YAML.load_file(f); puts f }' .github/workflows/*.yml
• bazel test //... (interrupted before completion to open the PR first, per request)