docs: document test attachments

[snevesbarros]

Summary

Documents test attachments (AnglesHQ/angles#133):

• Features: a new bullet listing logs, HAR files, videos, Playwright traces, HTML snapshots and images, with a viewer for each.
• Client libraries: a new "Attachments" subsection covering:
  • the four reporter methods (and their Python names)
  • that files upload against the build and work in batch mode
  • a table of extensions and how the UI shows each one
• Configuration reference: ANGLES_ATTACHMENT_MAX_SIZE_MB (default 100).
• Clean-up: notes that the nightly job removes attachments with their builds.

Merge after

AnglesHQ/angles#133, the UI PR and the client PRs, so the page doesn't describe features that aren't released yet.

Testing

• Built the site locally with Jekyll and jekyll-theme-slate.
• At a 412px phone width the page is still exactly 412px wide (the fix from fix(docs): fit the page to phone screens #4 holds). The new table and code block scroll inside the content column.

🤖 Generated with Claude Code

https://claude.ai/code/session_01KgQXSUjuLVXmLWxobnMfSf

---

Generated by Claude Code