Исправления GUI, кэша и парсинга ввода

[bivlked]

Что сделано

• не блокируем GUI при запросах к ЦБ: конвертация уходит в фоновую нить, кнопка временно блокируется
• нормализуем суммы с пробелами/разделителями тысяч и регистронезависимые коды валют
• кэш очищает устаревшие записи при каждом доступе/записи, чтобы TTL реально работал
• добавлена conftest-заглушка для опций --cov, чтобы pytest не падал без pytest-cov
• расширены тесты для новых кейсов

Проверка

• poetry run pytest -q

[codecov]

Codecov Report

❌ Patch coverage is 67.85714% with 18 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/currate/gui.py	19.04%	17 Missing ⚠️
src/currate/currency_converter.py	96.96%	1 Missing ⚠️

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Parse multi-group amounts without adding phantom decimals

The new parse_amount normalization treats any string with more than one separator as if the last separator were a decimal point (cleaned = ''.join(parts[:-1]) + '.' + parts[-1]), so an amount like "1.234.567"/"1,234,567" is parsed as 1234.567 instead of 1234567. This silently shrinks large integer inputs by three orders of magnitude rather than rejecting them, so conversions for million-scale values entered with standard thousand grouping will be wrong.

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