v0.254.0 — the saved notes follow the language, and the switch becomes a globe (R-557 slice 2 release C; SLICE 2 CLOSED)

The notes a background run SAVES — last night's backup line, the last error, the proof
result, the restore outcome — are written in the BOX's language at the moment they are
written. A household that switches sees the previous run's note in the old language until
the next run rewrites it: the operator's §16 option 1, stated rather than hidden.
EndRestoreOp no longer receives a Hungarian literal from anywhere.

The language switch is a globe. Two text links wrapped in the sidebar footer and asked the
reader to recognise "Magyar"/"English" as links; a globe is the one symbol every web user
already reads as "language", so nobody has to read Hungarian to escape Hungarian. It is
<details>/<summary> — a menu with no script, drawn inline because the icon sprite lives
only in layout.html and the visitor pages have their own shell.

Those visitor pages get the same globe, and a visitor's choice stays theirs: a display-only
felhom_lang cookie that langFor reads ONLY when there is no session. A signed-in household
can never inherit a language a previous visitor picked in the same browser. POST /lang is
CSRF-exempt for a narrow reason written at the exemption — its only achievable effect is the
language of the page the victim's own browser shows them — and safeBackPath refuses
//evil.example as well as https://, because "starts with /" alone is not the test. §16 taken:
a successful claim carries the cookie into the household's setting.

TWO PARITY EXCEPTIONS, MEASURED: 106 fixtures compared with a real diff — exactly two change
shapes (the dashboard footer, the globe in the shells) and 5 byte-identical, which are the
three pages that must not change.

I INTRODUCED A DEADLOCK AND THE SUITE CAUGHT IT BY HANGING. UpdateOffboxStatus holds the
settings write lock while running its callback; boxLang() wants the read lock; sync.RWMutex
is not reentrant. On a real box an off-site run would have hung forever HOLDING the settings
lock. Fixed by resolving the language before the callback, and guarded by a test that names
the file and line in a second instead of hanging for 25 minutes.

MinAgent: 0.131.0 (unchanged). No hub release needed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/web/templates/style.css

@@ -134,11 +134,22 @@ body {
     font-size: .8rem;
 }
 .version { color: var(--text-3); }
-/* i18n (v0.247.0): the language switch. Language names are shown in their own language, never translated. */
-.lang-switch { display: inline-flex; gap: 2px; margin: 0; }
-.lang-switch-btn { background: none; border: 1px solid var(--line); border-radius: var(--radius); color: var(--text-3); font: inherit; font-size: .75rem; padding: 0 .35rem; cursor: pointer; }
-.lang-switch-btn:hover { color: var(--blue-bright); }
-.lang-switch-btn.active { color: var(--text-1); border-color: var(--blue); }
+/* i18n (v0.254.0): the language switch is a GLOBE. Two text links wrapped in the sidebar footer and
+   asked the reader to recognise „Magyar"/„English" as links; a globe is the one symbol every web user
+   already reads as "language", so nobody has to read Hungarian to find their way out of Hungarian.
+   <details>/<summary> — a menu with no script: it opens on click and on Enter, and a screen reader
+   announces it. Language names inside are shown in their OWN language, never translated. */
+.lang-globe { position: relative; margin: 0; }
+.lang-globe-btn { list-style: none; display: inline-flex; align-items: center; color: var(--text-3); cursor: pointer; padding: .15rem; border-radius: var(--radius); }
+.lang-globe-btn::-webkit-details-marker { display: none; }
+.lang-globe-btn:hover, .lang-globe[open] .lang-globe-btn { color: var(--blue-bright); }
+.lang-globe-menu { position: absolute; bottom: calc(100% + .35rem); left: 50%; transform: translateX(-50%); margin: 0; padding: .25rem; list-style: none; min-width: 7.5rem; background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); z-index: 20; }
+.lang-globe-menu li { margin: 0; }
+.lang-globe-menu form { margin: 0; }
+.lang-globe-item { display: block; width: 100%; text-align: left; background: none; border: none; color: var(--text-2); font: inherit; font-size: .8rem; padding: .3rem .5rem; border-radius: var(--radius); cursor: pointer; white-space: nowrap; }
+.lang-globe-item:hover { color: var(--blue-bright); }
+.lang-globe-item.current { color: var(--text-1); font-weight: 600; }
+.lang-globe-item.current::after { content: " \2713"; }
 .logout-link { color: var(--text-3); text-decoration: none; transition: color 0.2s ease; }
 .logout-link:hover { color: var(--blue-bright); }
 /* Mobile chrome (v0.166.0) — hidden by default so desktop (>768px) stays pixel-identical; the
@@ -3664,3 +3675,10 @@ html::-webkit-scrollbar-track { background: var(--bg-0); }
 .restore-danger-card {
     border-left: 2px solid var(--crit);
 }
+
+/* i18n (v0.254.0): the globe on the pages a VISITOR meets — sign-in, claim, recovery. Those pages have
+   their own shell and no sidebar, so the globe is pinned to the top-right corner of the viewport, the
+   same place on all three. It posts to /lang, which sets a display-only cookie in that visitor's own
+   browser and never the household's setting. */
+.shell-lang { position: absolute; top: 1rem; right: 1rem; z-index: 30; }
+.shell-lang .lang-globe-menu { bottom: auto; top: calc(100% + .35rem); left: auto; right: 0; transform: none; }