Per the design brief's pivotal decision (discoverable-first, not syntax), replace
the operator-teaching placeholder (from:/is:unread/has:attachment) with a plain,
inviting 'Search your inbox…'. Operators still work; they're just not the thing
we put in a beginner's face.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
cesnimda