fix(relay): enforce protected route inventory

[cea-block]

Why

Protected authorization needs one machine-readable inventory so new or overlooked route and effect surfaces cannot silently bypass policy.

What

• Register protected relay, HTTP, moderation, workflow, media, Git, and audio operations with explicit capabilities and lifetime checkpoints.
• Fail closed when a protected route or effect lacks a complete policy classification.
• Gate workflow mutations and outbound effects through a provider-neutral authority interface.
• Preserve named compatibility exemptions outside the protected inventory.

Risk Assessment

The inventory is active only for protected authorization domains. Missing or inconsistent classifications deny protected operations, while named unprotected compatibility paths retain their existing behavior. No migrations are introduced.

References

Stacked on #4783.

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