[DEFERRED] Proactive low-balance and runway warnings

[krisoshea-eth]

Status

Tracking shell only. This is not current core work and must not be started without explicit maintainer promotion and bounded rescoping.

Why it remains useful

Operators may eventually need warning before the BN begins rejecting bids rather than only seeing an authoritative rejection.

Activation trigger

• Per-key pending-obligation semantics are defined.
• The intended multi-key operator model is defined.
• Maintainers agree thresholds or a runway model are reliable.
• A scoped Conditional package with owner, reviewer, evidence, and stop rule is approved.

Boundary

Core reports current BN status and balance when available and explains external top-up; it does not predict runway.

[linear-code]

LOD-40