Graceful error messages for project update validation failures

[dorkitude]

Problem

When linctl project update hits a GraphQL validation error (e.g., description too long), the error message is opaque:

❌ Failed to update project: GraphQL errors: [{Argument Validation Error [{3 4}] [projectUpdate]}]

This doesn't tell the user what actually went wrong or how to fix it.

Reproduction

linctl project update <project-id> -d "a description that is too long for Linear's field limit"

Expected behavior

A human-readable error message, e.g.:

❌ Failed to update project: description exceeds maximum length (250 characters)

Ideally linctl would parse known GraphQL validation errors and map them to friendly messages, with the raw error available via --verbose or similar.