v0.5.0 - Anthropic Files API support

Added

• Anthropic Files API support (beta files-api-2025-04-14)
  • Claudio.Files.upload/3 — multipart upload to /v1/files
  • Claudio.Files.list/2 — paginated listing with :limit, :before_id, :after_id
  • Claudio.Files.get/2 — fetch file metadata
  • Claudio.Files.download/2 — fetch raw file bytes (binary, not JSON-decoded)
  • Claudio.Files.delete/2 — delete a file
  • Uploaded files are referenced from messages via the existing Claudio.Messages.Request.add_message_with_document/4 helper (no API change required there)
  • Module grouped under "Files API" in ex_doc
  • Callers must opt in to the beta by passing beta: ["files-api-2025-04-14"] to Claudio.Client.new/2, or via config :claudio, :claudio, default_beta_features: ["files-api-2025-04-14"]

Full Changelog: v0.4.0...v0.5.0