Resets the deployment rotation policy to the DEFAULT template configuration.

This operation ensures the deployment always has a valid policy in place by:

1. Deactivating the current custom policy (if any)
2. Creating a new policy based on the DEFAULT template
3. Applying secure transition rules from the template

Unlike DELETE operations in tenant policies, deployment policies cannot be truly
deleted as they serve as the fallback for all tenants. This reset operation
guarantees system stability while returning to a known-good configuration.

The DEFAULT template provides secure algorithm transitions:
• requireOpsSubset: true (new key must support original operations)
• requireNoDowngrade: true (prevents weaker algorithms)
• allowClassicalToPqc: true (enables quantum-safe migration)
• allowPqcToClassical: false (prevents security downgrade)
• allowDifferentFamily: true (allows ML-KEM ↔ ML-DSA)