Catalog-only Provider wrapper for the Claude Code CLI.

The CLI protocol (Agentic.Protocol.ClaudeCode) handles the actual subprocess; this Provider wrapper exists so Claude Code shows up in Agentic.LLM.Catalog as an alternative pathway for the Claude family. The router groups it under the same canonical_id as Anthropic-direct and OpenRouter, then scores all three pathways via ProviderAccount.

availability/1

Three-state result (the proposal's graded availability):

• :unavailable — claude binary not on PATH
• :degraded — binary present but ~/.claude/auth.json is

               missing or expired (CLI re-auths lazily on first
               call; we still want the router to deprioritize)

• :ready — binary present and auth file is non-expired

Note: the Agentic.LLM.Provider behaviour does not yet declare an availability/1 callback. That's a follow-up; for now the function is plain Elixir and the router consumes it via Worth's ProviderAccount resolver.