docs(nodejs): steer agents to the right module system in code snippets

[mmanciop]

Summary

Node.js snippets across the otel-instrumentation skill mixed import and require without telling agents how to pick between them. An agent copying snippets into a project could produce SyntaxError: Cannot use import statement outside a module (ESM syntax in a CJS file) or ReferenceError: require is not defined in ES module scope (the reverse).

• Add a Module system in code snippets subsection to rules/sdks/nodejs.md with:
  • Detection rules (file extension, nearest package.json "type", surrounding code style, new-file default)
  • Explicit statement that all JavaScript snippets in the file default to ESM import
  • Translation table for import ↔ require, default/named/namespace forms, and export ↔ module.exports
  • Note that TypeScript source always uses import regardless of emit target
• Normalize the pg requestHook snippet in nodejs.md from require to import so all snippets in the file share one style.
• Switch the Node.js intro snippet in SKILL.md from require to import to match the ESM default.

Test plan

• Read rules/sdks/nodejs.md end-to-end and confirm no code snippet uses require( outside the translation table.
• Confirm SKILL.md intro snippet uses import.
• Verify the detection rules cover: .mjs/.cjs extensions, package.json "type", existing surrounding syntax, and new-file default.

🤖 Generated with Claude Code