fix: correct node/package.json main field to existing index.mjs

[cybermanhao]

Problem

node/package.json has:

{ "main": "../dist/node/index.js" }

But dist/node/index.js does not exist. The actual files present are:

• dist/node/index.mjs
• dist/node/index.cjs

Impact

Most environments are unaffected because Node.js and modern bundlers (webpack, rollup, etc.) resolve @google/genai/node via the parent package exports field, which correctly maps to index.mjs/index.cjs.

However, tools that fall back to subdirectory package.json main fields — such as tsx's custom ESM resolver — will encounter a Cannot find module error:

Error: Cannot find module '.../node_modules/@google/genai/dist/node/index.js'

Fix

Point main to the file that actually exists:

{ "main": "../dist/node/index.mjs" }

Notes

• The root cause of the user-visible error is in tsx's resolveDirectory bypassing the parent package exports map — that is a separate issue in tsx
• This fix makes the main field consistent with reality, which is a defensive improvement regardless

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