chore: add root editorconfig

[dnzbtc]

Summary

Adds a root-level .editorconfig to improve contributor consistency across editors and IDE environments.

Closes #2655

Changes

• added root .editorconfig
• standardized indentation and newline behavior
• improved editor consistency across contributors

[vercel]

@dnzbtc is attempting to deploy a commit to the Coinbase Team on Vercel.

A member of the Team first needs to authorize it.

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1

[ncnjdhc-afk]