As a WordPress site, my Compatibility Tool should have better tooling for evaluating plugins' AMP compatibility programmatically.

• AC1: Currently, AMP validation only occurs on plugin activation and when editing a post: This story addresses user experience. We would like to additionally allow a site admin to manually trigger a check of the plugins' AMP compatibility inside the user interface from [Compatibility Tool] Improve experience for user based on AMP compatibility #1006 via WP-CLI.
• AC2: A validation test should be able to evaluate an entire site even if AMP theme support is not declared yet. (i.e. Be able to force the equivalent of AMP theme support when crawling.)
• AC3: The compatibility tool should be able to target the various templates that now are presented to the user (as as described by @westonruter below, related Add support for allowing a site subset to be native AMP #1235.)

The goal is to spawn validation process and get results programmatically for an entire site. WP-Cron and WP-CLI are in view here, as is integrating with logic in XML Sitemap generators to obtain list of URLs potentially.