feat: implement per-language escaping calculation in Token

[pleberre]

Problem

String escaping logic needs to be properly customized per language, as different languages have different escaping rules.

File Location

src/main/java/io/err0/client/core/Token.java:52

// FIXME: per-language do the escaping calculation

Context

Different programming languages have different string escaping rules:

• Java/C/C++: \n, \t, \", \\
• Python: \n, \t, \", \', raw strings r"..."
• JavaScript: \n, \t, \", \', template literals
• Go: \n, \t, raw strings with backticks
• Rust: \n, \t, raw strings r#"..."#

Current Behavior

Likely using a generic escaping approach that may not handle language-specific nuances.

Expected Behavior

• Correctly handle escaping for each of 14+ supported languages
• Account for language-specific string literal types (raw strings, template literals, etc.)
• Preserve semantic meaning of escaped sequences

Implementation Guidance

Step 1: Create Language-Specific Escaping Interface

public interface StringEscapeHandler {
    String escape(String input);
    String unescape(String input);
}

Step 2: Implement for Each Language

public class JavaEscapeHandler implements StringEscapeHandler { ... }
public class PythonEscapeHandler implements StringEscapeHandler { ... }
// etc.

Step 3: Update Token Class

public class Token {
    public String getEscapedContent(Language language) {
        StringEscapeHandler handler = EscapeHandlerFactory.getHandler(language);
        return handler.escape(this.content);
    }
}

Test Cases Needed

For each language, test:

• Simple escape sequences (\n, \t)
• Quote escaping (\", \')
• Backslash escaping (\\)
• Language-specific features (raw strings, template literals)
• Edge cases (empty strings, only escapes, etc.)

Reference

• Apache Commons Text StringEscapeUtils for reference implementations
• Language specifications for each supported language

Acceptance Criteria

• Per-language escape handlers implemented for all 14+ languages
• Token.java FIXME removed
• Comprehensive tests for each language
• Documentation of escaping rules per language
• No regressions in string handling