Evaluate instrumentation for Files API

The OpenAI integration does not instrument file management endpoints. These are supporting operations (uploading training data, batch inputs, etc.) rather than inference calls.

**Endpoints to evaluate:**

* `openai.resources.Files.create()` (upload)
* `openai.resources.Files.retrieve()`
* `openai.resources.Files.list()`
* `openai.resources.Files.delete()`
* `openai.resources.Files.content()` (download)

**Decision needed:**
Determine whether lightweight instrumentation (file ID, purpose, size) would provide useful telemetry, or if this is out of scope for GenAI monitoring. Consider that file operations are ancillary to the core inference/generation use cases.

**Reference:** [OpenAI integration compliance review](<../openai-integration-compliance-review.md>), Section 6