Closes #7463

Summary by cubic

Restores CommonJS compatibility by pointing axios's main entry to the built CJS bundle so require('axios') works in Node again. ESM exports are unchanged.

Description

• Summary of changes: Set "main" to ./dist/node/axios.cjs in package.json.
• Reasoning: Fixes the CJS require regression (fixes axios version 1.13.6 package.json "Cannot use import statement outside a module" in node 12 #7463).
• Additional context: "module" and "exports" stay the same; ESM and browser builds are unaffected.

Testing

• No tests changed.
• Recommend adding a smoke test that require('axios') loads successfully and exposes expected APIs (e.g., axios.get).

^{Written for commit 652b68c. Summary will update on new commits.}