Support Short Flags for Frequently Used CLI Options

[K-dash]

Overview

Users type several long flags (--project-number, --location, --endpoint-location, etc.) every time they run the CLI. Providing short aliases would make the day-to-day experience smoother—especially for doctor and notebooks commands where these options are required or frequently set.

Proposal

Add single-letter (or clear two-letter) shortcuts to the global options:

• -p → --project-number
• -l → --location
• -e → --endpoint-location
• -a → --auth
• -t → --token

Update Clap definitions in GlobalArgs, document the new flags in the README/CLI doc, and add a CLI integration test that exercises at least one short-flag path (e.g., nblm doctor -p … -l …).

Why it matters

• Reduces typing overhead for heavy CLI users
• Makes scripts and examples less noisy
• Matches expectations from other CLIs that provide both long and short forms

Stretch ideas (optional follow-up)

• Consider short flags for subcommand-specific options once we gauge demand
• Add a cheatsheet table in the docs showing long ↔ short mapping