R-299: the orphan card's second promise, and a guard that matched one inflection

The explanation paragraph - the always-visible half of the card - still ended
'a hozzajuk tartozo helyreallitasi koddal kesobb visszaallithatok lehetnek',
the same unevaluable claim v0.211.0 removed from the confirm block below it.

It survived because the spec called that line accurate, and because the
regression guard asserted the SINGULAR form while the card carried the plural,
which does not contain that substring. The guard now matches the stem, so any
conjugation fails it. The two accurate halves are kept.

Also: the guard's failure message sliced rendered HTML at a byte offset and cut
Hungarian mid-character; it now slices on rune boundaries.

CHANGELOG.md

@@ -1,3 +1,34 @@
+## v0.212.0 — the second promise (2026-08-12, R-299) — MinAgent 0.127.0
+
+**R-299 — the orphan card’s OTHER sentence made the same unevaluable promise, and the spec said it was
+fine.** v0.211.0 fixed the confirm block; the EXPLANATION paragraph above it
+(`internal/web/templates/backups_remote.html`) still ended *„a hozzájuk tartozó helyreállítási kóddal
+később **visszaállíthatók lehetnek**”* — the identical claim in the plural.
+
+**It survived for two independent reasons, and both are the interesting part:**
+
+1. `SPEC-orphan-card-copy-2026-08-10.md` §1 listed that line as *“Accurate; keep”*. The spec has been
+   corrected.
+2. **The regression guard matched one INFLECTION.** It asserted `visszaállítható lehet` (singular); the
+   card carried `visszaállíthatók lehetnek` (plural), which does not contain that substring at all. **A
+   guard matching one inflection of a Hungarian verb guards one sentence, not the claim.** It now
+   matches the stem `visszaállíthat`, so any conjugation fails. Proven by planting the exact shipped
+   plural: the stem guard convicts and quotes it, while the old singular guard does not match it.
+
+**And it was the ALWAYS-VISIBLE half.** The paragraph fixed in v0.211.0 renders only after the customer
+clicks „Új távoli mentés indítása…”. On first view the explanation is the only text they read — so
+until now, the sentence a customer actually saw was the one still promising.
+
+**The two accurate halves are kept**, because declining a promise must not turn into telling the
+customer less than we know: the store IS orphaned (and why), and new backups genuinely cannot be
+written. New ending: *„A meglévő mentések nem sérültek. Azt viszont ez a gép nem tudja megállapítani,
+hogy később megnyithatók-e — ez attól függ, megvan-e még a hozzájuk tartozó kulcs. Ha szükséged van
+rájuk, írj nekünk.”*
+
+Also fixed in the guard itself: its failure message sliced the rendered HTML at a BYTE offset, which
+cuts Hungarian mid-character and printed a replacement char — a garbled failure message reads like an
+encoding bug in the product. It now slices on rune boundaries.
+
 ## v0.211.0 — the wall a rebuilt box could not get past (2026-08-10, R-280 / R-294 / R-295) — MinAgent 0.127.0
 
 **R-294 / R-202 — the orphan card stops promising what it cannot know.** The card told a customer,