WR492688: Issue #32
Fix: the 'static' flag can no longer be set from a raw client value. It
is now only true if the request presents a 'statickey' matching an
HMAC-SHA256 of the outage id keyed with a per-site secret
(infopage::statickey(), lazily generated via set_config()/get_config()).
maintenance_static_page::create_from_outage() now sends that computed
statickey instead of static=1 when it internally fetches info.php, so
the legitimate static-generation path keeps working while external
forgery of the flag is no longer possible.
WR492688: Issue #33
WR492688: Version bump