Qualify StageRouter and escalation for NemoClaw-managed Hermes

Parent Epic: #7937

Depends on the stable V4 platform integration and managed E2E.

## Outcome

Qualify the remaining Switchyard 0.2 router families for NemoClaw-managed Hermes instead of assuming platform integration makes every algorithm supported.

## Scope

- StageRouter: stage configuration, per-stage model selection, budgets, state, feedback, and fallback.
- Response-judging escalation: judge protocol, thresholds/streak/latching, stable `x-switchyard-session-id`, feedback, and fallback.
- Validate OpenAI Chat/Responses and Anthropic serving protocols only where the released plugin supports them.
- Record known attribution, cancellation, retry, and buffered-upstream limitations.

## Acceptance

- [ ] Each supported router has a versioned configuration schema and owner.
- [ ] Deterministic and live tests prove its routing state transitions and selected real targets.
- [ ] Session-scoped escalation persists only for the intended session and resets under documented conditions.
- [ ] Unsupported judge/protocol combinations are rejected before readiness.
- [ ] Failure and fallback semantics are independently tested for each router family.
- [ ] Benchmark or quality claims link to #8501 evidence rather than this integration alone.