docs: note local dev workspace context.

[arntiloop]

Summary

• Add a note under the Local development example explaining that the yarn workspace commands should be run from the repository root.

Rationale

• Makes it clearer how workspace resolution works and reduces mistakes when starting individual apps in the monorepo.

[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

[vercel]

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

A member of the Team first needs to authorize it.