fix(pricingRegistry): normalize model names to lowercase for case-insensitive lookup

[Srejoye]

[Srejoye]

Hi @maintainer,

I’d like to work on this issue under GSSoC’26.

I analyzed the issue in src/core/pricingRegistry.ts. Currently, register() normalizes the provider name to lowercase but stores model identifiers exactly as provided. getPricing() and hasPricing() also perform case-sensitive model lookups.

Because of this, registrations like registerPricing("openai", "GPT-4o", {...}) will fail to match runtime responses returning "gpt-4o". The lookup then misses pricing data, causing calculateCost() to silently return $0 and bypass budget accounting entirely.

Proposed fix:

• Normalize model identifiers using model.toLowerCase() in:

  • register()
  • getPricing()
  • hasPricing()

• Add unit tests verifying case-insensitive model registration and lookup behavior

• Preserve all existing APIs and built-in pricing registrations

This is a minimal and low-risk fix with no public API changes. Please assign this issue to me. Thanks!