Feature: authentication support (-u basic auth, --cookie, bearer tokens)

[korya]

Problem

There are no authentication conveniences. Anything non-public requires hand-rolling headers:

http-assert -H "Authorization: Basic $(printf 'user:pass' | base64)" …
http-assert -H "Cookie: session=abc123" …

Proposed

-u, --user user:password   Use basic authentication
    --bearer token         Set an Authorization: Bearer header
-b, --cookie name=value    Send a cookie (repeatable)

Why it matters

Health checks on authenticated endpoints are common, and base64-in-a-subshell is both awkward and a good way to leak credentials into shell history and CI logs. A -u flag can also read from an environment variable to avoid that.