feat: accept --verbose as a global flag before the subcommand

[HelenGreul]

Problem or motivation

--verbose currently only works when placed after the subcommand:

poly push --verbose   ✅ works
poly --verbose push   ❌ fails

This is non-standard. Every major CLI that has global flags (git, kubectl, gh, docker) accepts them before the subcommand. Developers build muscle memory from these tools and will naturally try poly --verbose push when debugging, hit a confusing parse error, and not understand why.

Proposed solution

Accept --verbose in both positions by hoisting it to the top-level parser:

poly --verbose push    # global position — works
poly push --verbose    # after subcommand — still works (backwards compatible)

Argparse supports this via parser.add_argument('--verbose', ...) on the root parser in addition to (or instead of) each subparser. The value can be propagated to subcommand handlers the same way it is today.

Alternatives considered

Keeping --verbose subcommand-only and just documenting the position requirement. This avoids a parser change but doesn't fix the underlying ergonomic mismatch with developer expectations.

Scope

CLI commands