* feat(models): add Claude Opus 5 support
* test(models): align Opus 5 setup fixtures
* test(models): update ambient Opus 5 detection
* fix(models): reconcile Opus 5 support with main
User-facing name is now OpenClaw (the system speaks); internal code name is
system-agent. Gateway methods crestodian.* -> openclaw.chat/openclaw.setup.*,
agent tool -> openclaw, reserved agent ids openclaw + retired crestodian.
openclaw setup routes: onboarding flags -> onboard, -m/--yes -> system agent,
bare configured interactive -> OpenClaw chat, unconfigured -> onboarding.
Hidden crestodian CLI and /crestodian TUI aliases kept; docs moved to
docs/cli/openclaw.md with redirect stub. macOS/Android strings in lockstep.
Refs #107237