feat(typescript): implement exception classname metadata extraction

[pleberre]

Problem

The TypeScript parser does not extract exception classname metadata, resulting in incomplete error tracking data.

File Location

src/main/java/io/err0/client/languages/TypescriptSourceCodeParse.java:329

// TODO: extract exception classname meta data

Context

TypeScript has try-catch blocks similar to JavaScript but with type information:

// Standard Error
throw new Error("message");

// Custom error classes
class MyCustomError extends Error {
    constructor(message: string) {
        super(message);
    }
}

throw new MyCustomError("custom error");

// Try-catch
try {
    doSomething();
} catch (error: MyCustomError) {
    // Handle specific error type
}

Expected Behavior

Extract and store:

• Error class names from throw statements
• Error types from catch clauses
• Custom error class definitions
• Standard Error subclasses

Implementation Guidance

1. Identify TypeScript error patterns:

   • throw new ErrorType() statements
   • catch (error: ErrorType) clauses
   • Error class definitions extending Error
   • Type annotations on error objects

2. Extract error type information:

   • For throw new X(): extract "X"
   • For catch (e: X): extract "X"
   • For class definitions: extract class name if extends Error

3. Store in token metadata

4. Handle TypeScript-specific syntax:

   • Type annotations
   • Generic error types
   • Union types in catch clauses

Test Cases Needed

Add to src/test/testdata/ for TypeScript:

• Throw with Error class
• Throw with custom error
• Catch with type annotation
• Custom error class definition

Reference Files

• src/main/java/io/err0/client/languages/JavascriptSourceCodeParse.java (base implementation)
• src/main/java/io/err0/client/languages/JavaSourceCodeParse.java (exception handling pattern)

Acceptance Criteria

• Exception class names extracted from TypeScript error patterns
• Type annotations properly parsed for error types
• TODO removed from TypescriptSourceCodeParse.java:329
• Tests pass for TypeScript error handling
• No regressions in existing TypeScript parsing