fix(cli): handle top-level version flag

[adity982]

What & why

Handle --version before the missing-command usage branch so a conventional top-level version probe prints the version and exits successfully. This fixes install scripts and CI probes that currently abort on exit code 2.

Closes #4

Changes

• Move the version flag handling ahead of the bare-invocation help branch.
• Add regression coverage for top-level --version output and exit status.
• Pin the neighboring bare invocation (exit 2) and explicit help (exit 0) behavior.

Validation

npm test
PASS — 7 files, 53 tests

npm run typecheck
PASS

npm run build
PASS

git diff --check
PASS

Checklist

• Focused change with a clear description
• Ran lint/typecheck, build, and tests
• No documentation change is needed; --version is already documented
• Linked related issue with Closes #4

[github-actions]

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