Record the community-facing framing for why indexability is the default rather than an opt-in question.

Making opted-in abstract articles crawlable is a deliberate design choice that can be defended on two grounds. First, parity: the pilot is evaluating whether abstract content is a viable mainspace experience, and mainspace content on WMF wikis is indexable by default; a non-indexable opt-in would be a second-class mainspace surface and would not test what we are trying to test. Second, discoverability: without external indexability, readers reach opted-in articles only by direct link-sharing or through the M3 stretch milestone's internal search integration (which is explicitly not in the Q1 scope), so declining to index would mean the pilot's content is effectively unreachable in Q1. The framing matters because this is the kind of decision that will attract community commentary on the public Phabricator task, and recording the justification in the planning doc means the reasoning travels with the work rather than being re-derived in ad hoc replies later.