CSV import fails for files containing non-ASCII characters (UTF-8)

When importing a CSV statement exported from Bank of Georgia containing Georgian characters, MoneyMatter rejects the file with the following error:

bog.csv doesn't appear to be a valid CSV file. The file may be binary or renamed.

Root cause:

In file-validator.ts, the isValidTextContent() function considers only printable ASCII bytes as valid text and requires more than 90% of the file content to match. UTF-8 characters (e.g., Georgian, Cyrillic) fail this validation.

Expected behavior:

Valid UTF-8 CSV files should be accepted regardless of the language used in headers or transaction descriptions.

Suggested fix:

Replace the ASCII-based validation with proper UTF-8 text validation while still rejecting binary files.