Quoted default values aren't escaped: a " or \ in DefaultValue generates C# that doesn't compile #111

What's wrong

TemplateBase.WriteDefaultValueTo (CodeBlocker/Templates/TemplateBase.cs:96) wraps the value as $"\"{DefaultValue}\"" when DefaultValueIsQuoted is set, without escaping it. This affects FieldTemplate, ParameterTemplate, PropertyTemplate and EnumMemberTemplate.

Reproduction (ran)

new FieldTemplate { Type = "string", Name = "p", DefaultValue = @"C:\temp\""x""", DefaultValueIsQuoted = true }

The value is the raw text C:\temp\"x".

• Actual output: private string p = "C:\temp\"x"";
  • This doesn't compile (unterminated literal).
  • Even without the quote, \t would silently become a tab.
• Expected output: private string p = "C:\\temp\\\"x\"";

Why it matters

DefaultValueIsQuoted exists so callers can pass a raw string value, and the obvious inputs for it are paths, regexes, JSON snippets and messages containing quotes. Each of these produces broken or silently altered generated code. In a source generator the result is a compile error in the consumer's project, far from the cause.

Suggested fix / acceptance criteria

• Escape \, ", \r, \n, \t, \0 and other control characters (\uXXXX) before quoting. Alternatively, use SymbolDisplay.FormatLiteral(value, quote: true) if taking a Roslyn dependency is acceptable, or emit a verbatim @"..." literal with " doubled.
• Add tests with a backslash, a quote, and a newline in DefaultValue, each asserting the literal round-trips.