_external_process_spec asked PATH only (shutil.which) for a provider's
process_command, so a backend started by a LaunchAgent or Hermes Desktop
(bare PATH) reported 'claude' missing even when it lived in
~/.local/bin, ~/.claude/local, ... -- the prefixes agent/anthropic_adapter
already probes for version detection. run_oauth_setup_token had the same
PATH-only lookup.
Add anthropic_adapter.find_claude_code_cli(), which resolves a bare
claude/claude-code name via hermes_platform's locate_command over the
adapter's existing _CLAUDE_CODE_PREFIXES, and use it on a PATH miss in
_external_process_spec and in run_oauth_setup_token. PATH hits and every
other command are unchanged.