Notation like Home Assistant, each screen in its own language, and the language in every build

From the end-to-end test on the bench boards and an independent review:
- Units spaced as Home Assistant does (54% / 54 % in German and French, 18°, 21.5 °C), in the firmware and the app.
- Grouping from five digits where the language does (1234 but 12.345 in Spanish, Polish, Portuguese): the layout
  message carries group_min and percent_space; an unknown number style no longer refuses a layout.
- Automatic follows Home Assistant's own language for the clock and numbers, also without a translation (Swedish:
  24 hours, 1 234,5; pt-BR: 1.234,5): regions.json from the CLDR for all 63 languages Home Assistant offers.
- 12-hour clock: the top bar says 3:48 PM, the clock card 3:48 (not 03:48), Last runs follow the clock.
- The climate setpoint font has the decimal comma; the value fonts have ², ³ and µ (m³ was a box).
- Weather days: at most three letters without the dot (mié, sáb, czw); the screen took three bytes.
- Texts fall back per key through the base language (pt-BR -> pt -> en) in the firmware and the app.
- Each screen gets the app's words in the language its firmware speaks; firmware from before the languages gets
  English and its own letters, not boxes.
- set_language re-reads what it writes (indentation, comments, quoted keys, CRLF, !include) and every build writes
  the language first; the 24-hour pin no longer hits a fresh install and waits for the old clock switches.
- Tests: region and notation, plural parity with the C++ rules, set_language edge cases, the pin, PUT /api/language.

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

tools/i18n.py

@@ -7,7 +7,8 @@
     python3 tools/i18n.py header [--check]  write (or compare) the key header and the tests' English table that the
                                             firmware's `screen` texts need, after changing the keys of en.json
     python3 tools/i18n.py cldr [--write]    day and month names, date orders and the decimal mark from the Unicode CLDR
-                                            (Node's Intl), into every language's screen.date and screen.number
+                                            (Node's Intl), into every language's screen.date and screen.number, and the
+                                            clock and numbers of every Home Assistant language (screen_manager/app/regions.json)
     python3 tools/i18n.py ha-words [--write] Home Assistant's own words for states (screen.ha) in every language, from a
                                             Home Assistant (HA_URL and HA_TOKEN); needs aiohttp
     python3 tools/i18n.py new CODE NAME ENGLISH PLURAL
@@ -38,7 +39,8 @@ def generator():
 
 def languages():
     """{code: data} of every language file, English first."""
-    found = {path.stem: json.loads(path.read_text(encoding='utf-8')) for path in sorted(FOLDER.glob('*.json'))}
+    found = {path.stem: json.loads(path.read_text(encoding='utf-8')) for path in sorted(FOLDER.glob('*.json'))
+             if re.fullmatch(r'[a-z]{2,3}(-[A-Za-z0-9]{2,8})?', path.stem)}
     return dict(sorted(found.items(), key=lambda item: (item[0] != 'en', item[0])))
 
 
@@ -330,6 +332,40 @@ def main():
 
 # The CLDR locale of a file where it differs: Portuguese is Home Assistant's pt, the one of Portugal.
 CLDR_LOCALE = {'pt': 'pt-PT'}
+# Every language Home Assistant's frontend offers (2026.9: the languages of its translationMetadata). A language ESP
+# Screens has no file for still writes the clock and numbers as Home Assistant does (regions.json); its texts fall back
+# to English.
+HA_LANGUAGES = ('af ar bg bn bs ca cs cy da de el en en-GB eo es et eu fa fi fy fr ga gl gsw he hi hr hu hy id it is ja '
+                'ka ko lb lt lv mk ml nl nb nn pl pt pt-BR ro ru sk sl sr sr-Latn sv sq ta te th tr uk ur vi zh-Hans '
+                'zh-Hant').split()
+# The languages that put a space between a number and "%" ("54 %"), as Home Assistant's frontend does
+# (src/common/translations/blank_before_unit.ts, blankBeforePercent); every other one writes "54%".
+HA_PERCENT_BLANK = ('cs', 'de', 'fi', 'fr', 'sk', 'sv')
+REGIONS = ROOT / 'screen_manager' / 'app' / 'regions.json'
+
+
+def percent_space(code):
+    return code.split('-')[0] in HA_PERCENT_BLANK
+
+
+def number_style(number):
+    """point (1,234.5), comma (1.234,5) or space (1 234,5): the choices of Settings -> Language & region."""
+    if number['decimal'] != ',':
+        return 'point'
+    return 'space' if number['group'].strip() == '' else 'comma'
+
+
+def regions():
+    """{code: {clock, numbers, group_min, percent_space}} for every Home Assistant language, from Node's Intl."""
+    locales = [CLDR_LOCALE.get(code, code) for code in HA_LANGUAGES]
+    found = json.loads(subprocess.run(['node', str(ROOT / 'tools' / 'i18n_cldr.mjs'), *locales], check=True,
+                                      capture_output=True, text=True).stdout)
+    table = {}
+    for code, locale in zip(HA_LANGUAGES, locales):
+        cldr = found[locale]
+        table[code] = {'clock': cldr['clock'], 'numbers': number_style(cldr['number']),
+                       'group_min': int(cldr['number']['group_min']), 'percent_space': percent_space(code)}
+    return table
 
 
 def write_language(code, data):
@@ -360,11 +396,21 @@ def cldr_dates(write, codes=None):
         cldr = found[locale]
         before = json.dumps(data, ensure_ascii=False)
         data.setdefault('_meta', {})['clock'] = cldr['clock']
-        merge(data.setdefault('screen', {}), {'number': cldr['number'], 'time': cldr['time'], 'date': cldr['date']})
+        number = {**cldr['number'], 'percent': ' %' if percent_space(code) else '%'}
+        merge(data.setdefault('screen', {}), {'number': number, 'time': cldr['time'], 'date': cldr['date']})
         if json.dumps(data, ensure_ascii=False) != before:
             print(f'{code}: {"wrote" if write else "would change"} the CLDR texts')
             if write:
                 write_language(code, data)
+    table = regions()
+    text = json.dumps({'_about': 'GENERATED by tools/i18n.py cldr: how every Home Assistant language writes the clock and '
+                                 'numbers (Unicode CLDR, Home Assistant\'s own rule for the space before %). The app takes '
+                                 'it for Settings -> Language & region set to Automatic.', **table},
+                      ensure_ascii=False, indent=1) + '\n'
+    if not REGIONS.exists() or REGIONS.read_text(encoding='utf-8') != text:
+        print(f'regions.json: {"wrote" if write else "would change"} the clock and numbers of {len(table)} languages')
+        if write:
+            REGIONS.write_text(text, encoding='utf-8')
     return 0