The 10% growth tolerance goes red a day after a refresh, and passes a card mistyped inside 10%

[realmarcin]

From the round-1 review of #212 (issues #148, #113).

Where: scripts/fleet/check_cards.py classify() and GROWTH_TOLERANCE, and _fleet/README.md:189.

Problem 1: the tolerance doesn't cover a refresh interval. CellStructureMech adds about 2 records an hour, roughly 9% a day against its 542 card. The 10% figure came from a single lead measured 17 hours after the pins (6.5%), not from growth over the time between refreshes.

• classify(542, 596) returns grew and classify(542, 597) returns STALE.
• The 07:23Z nightly on 2026-09-26 would therefore fail again.
• That is the standing red check_cards.py cannot tell a site that grew past a pinned card from a wrong card #148 and The nightly card check stays red for Mechs that publish after a refresh's pins #113 describe, put off by about a day.
• README line 189 ("reports both as grown, a warning, until the next refresh") would soon be false.

Problem 2: a mistyped card inside 10% only warns. Say HabitatMech's card is typed 3,026 instead of 3,206. The live page is byte-identical to the pin (site_html_sha256 == site_html_sha256_at_pin), so the site can't have grown. The check still prints "grew ... +5.9%" and exits 0. site_audit.json already holds the pinned page hashes, and the check doesn't read them.

Fix: base the verdict on the audit, not on a fixed percentage:

• Wrong card: fail when the live source is byte-identical to its pinned copy but states a different figure.
• Growth: a warning for a bounded time after pinned_at_utc, and a failure after that.