1.0.0

Initial commit: re-prime the W3TC page cache after purges

Listens to W3TC's public flush actions (w3tc_flush_post / w3tc_flush_url)
and fires non-blocking loopback requests on shutdown at priority 200000 -
after W3TC executes its queued purges at 100000 - so purged pages are
re-cached before a real visitor arrives. Inline priming does not work:
it gets served the old cached page, which W3TC then deletes.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>