Playbook Validate

Validate the playbook file at the path the user supplied ($ARGUMENTS). A playbook drives automated or semi-automated remediation during an incident, so a malformed one is a safety hazard.

Checks

1. Required fields - each playbook has: id, name, trigger (fault class / IncidentMode / signal), steps, owner, severity. Each step has: id, description, action, idempotent (bool), rollback, requires_authorisation (bool), timeout.
2. Step ordering - steps form a sane sequence: detect/confirm → contain → remediate → verify. No remediation step runs before the triggering condition is confirmed.
3. Idempotency - every step declares idempotent; any non-idempotent step documents why re-running is unsafe and how it is guarded.
4. Rollback - every state-changing step has a rollback (or an explicit, justified rollback: none for read-only steps).
5. Authorisation - any production-affecting step sets requires_authorisation: true; cross-check against the AEGIS_PROD_CONFIRMED guard convention.
6. Consensus weights - consensus weight is a default_weight ClassVar on each agent class (src/aegis_swr/agents/), not a file: check every registered agent declares a numeric weight and the built-in roster sums to ~1.0 (±0.01).

Output

## Playbook Validation - <file>
**Verdict: VALID | INVALID**
### Errors (blocking)
- <field/step> - <problem>
### Warnings
- <improvement>
### Coverage
- steps: N | with rollback: N | idempotent: N | needs-auth: N

Default to INVALID if any required field is missing or any state-changing step lacks a rollback.