Speak the app's own texts from the translations: its messages and labels in the editor's language, the words it sends the screens in theirs

Every error, delivery status, update result and label the editor shows is an `addon` text of en.json now, in the language
of the editor's request: its X-ESP-Screens-Language header, or ?language= for the live updates, which an EventSource sends
without headers. A text made in the background and read later (a delivery status, an update result in updates.json, why a
screen can't show an alert) is kept in English with its key (i18n.Text, i18n.english) and written in the editor's language
when it is shown (i18n.shown); updates.json keeps the English message next to the key, for an older app.

The words the app sends to the screens come in the screens' language (Settings -> Language & region): the names of the
built-in tiles, the top bar's words, dates and numbers, the history card's words, the vacuum chips, the forecast's day
names and the Identify card, and so does the notification of a stopped update round. The top bar and the history card
take a binary sensor's words from screen.ha.binary, as the tiles do, which makes test_binary_words pass again; three tests
follow Home Assistant's new words there (Detected, Clear).

What stays English: what Home Assistant gets as data (a tile event's answer, the layout sensors, entity names), the logs
and the firmware jobs' logs, the screens' protocol words, and the Claude skill, which is built from the English tables in
core.py and tile_icons.py; en.json repeats those and tests/test_addon_translations.py keeps both equal.

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

screen_manager/app/claude_skill.py

@@ -11,6 +11,7 @@ import os
 from pathlib import Path
 import zipfile
 
+from i18n import t
 import tile_icons
 from core import (ALERT_CAMERA_FIELD, ALERT_ENDINGS, ALERT_EVENT, ALERT_FALLBACK_ICON, ALERT_FIELDS, ALERT_LIMITS, ALERT_MAX_TIMEOUT,
                   ALERT_MIN_FIRMWARE, ALERT_SUGGESTED_ICONS, AUTO_STANDBY_MIN_FIRMWARE, BROADCAST_DISMISS, BROADCAST_SHOW,
@@ -433,5 +434,5 @@ def install(directory):
         temp.write_text(text(), encoding='utf8')
         temp.replace(directory / 'SKILL.md')
     except OSError as error:
-        raise ValueError(f"Couldn't write the skill to {directory} ({error.strerror or type(error).__name__}).") from error
+        raise ValueError(t('addon.errors.skill_not_written', folder=directory, reason=error.strerror or type(error).__name__)) from error
     return {**status(directory), 'restart': restart}