fix: INI newline injection in backtest config generation

Add ini_safe() helper that strips CR/LF from user-supplied string params
before they are written into terminal.ini and backtest_config.ini.
Applies to: expert path, symbol, timeframe, set_file — any value that
could carry an embedded newline and inject extra INI directives.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Cargo.lock

@@ -481,7 +481,7 @@ dependencies = [
 
 [[package]]
 name = "mt5-quant"
-version = "1.32.2"
+version = "1.32.1"
 dependencies = [
  "anyhow",
  "base64",