030 ai error explanation

// Test: AI-powered compiler error explanation
//
// When compilation fails, the compiler can invoke an AI to explain the error.
// This is a PIPELINE PASS, not magic - just another step in compiler.coordinate.
//
// The test verifies:
// 1. AI is invoked when OPENROUTER_API_KEY (or similar) is set
// 2. Response matches ErrorExplanation schema (summary, cause, fix)
// 3. Response references relevant Koru constructs, not just Zig internals
//
// Non-deterministic output is tested via SCHEMA VALIDATION, not exact match.
// The AI's explanation varies, but it must fill the required slots.

// This code has an intentional error for the AI to explain
~event broken.example {
    value: NonexistentType,  // ← This type doesn't exist
}
| ok {}

~proc broken.example {
    return .{ .ok = {} };
}

~broken.example(value: 42)