fix(prism): delegate structured/embeddings/images calls in TracingProvider

[olivM]

Summary

Fixes: Structured is not supported by TracingProvider (and the same class of error for embeddings(), images(), moderation(), textToSpeech(), speechToText(), stream()) when using the Prism auto-instrumentation driver.

Root cause

Prism's base Prism\Prism\Providers\Provider class defines concrete (non-abstract) default methods for structured(), embeddings(), images(), moderation(), textToSpeech(), speechToText(), and stream(). Each throws:

throw PrismException::unsupportedProviderAction($method, class_basename($this));
// e.g. "Structured is not supported by TracingProvider"

Cybernerdie\Glint\Instrumentation\Prism\TracingProvider extends Provider but only overrode text(). Since the other methods are already concrete on the parent (not abstract), PHP resolves calls to them directly against the inherited implementation instead of falling through to TracingProvider::__call(). That means $this inside the thrown exception is the TracingProvider wrapper, not the real underlying driver — so the error always says "TracingProvider" regardless of which provider (OpenAI, Anthropic, Ollama, etc.) is actually configured, and the call never reaches the real driver even when it does support the action.

Fix

TracingProvider now explicitly overrides structured(), embeddings(), images(), moderation(), textToSpeech(), speechToText(), and stream(), delegating to the wrapped provider via the existing callInner() helper (same pattern already used for text()). If the wrapped provider doesn't support the action either, the error now correctly names that provider instead of TracingProvider.

Tests

The bug wasn't caught previously because the test double at tests/Stubs/Prism/Providers/Provider.php was just abstract class Provider {} — it didn't reproduce Prism's real default-throwing behavior. This PR:

• Updates the stub Provider class to mirror the real package (default methods that throw "X is not supported by {class}").
• Adds the minimal stub request/response classes needed (Structured, Embeddings, Images, Moderation, Audio, Exceptions\PrismException).
• Adds regression tests proving TracingProvider now correctly delegates structured()/embeddings() when the wrapped provider supports them, and that the "unsupported" error names the wrapped provider (e.g. Anthropic), never TracingProvider.
• Fixes an existing test that overrode embeddings() with an incompatible signature (now fatal once the stub declares the real signature).

Checks

• composer test — 619 passed
• composer stan — no errors
• composer pint — passed

[cybernerdie]

Hey @olivM , awesome find, and great write-up in the PR description!, this has been tested

Thanks for the contribution, really appreciated! 🙌