fix(garm): skip blocked exact retry intents

[rldyourmnd]

Outcome

• publish GARM derivative v0.2.1-nddev.80
• retain terminal/deferred exact-job retry state without repeatedly reserving that same job
• select the oldest eligible unclaimed admitted sibling intent in the scale set
• fail closed without mutation when every exact intent is blocked

This removes per-scale-set head-of-line blocking after one job exhausts its three infrastructure attempts. It does not retry the terminal job, delete its live intent, change queue priority, or bypass shared capacity admission.

Verification

• make verify
• full upstream overlay vet and race suite
• two network-disabled reproducible GARM builds
• binary SHA-256 5f4e5177044f0a3bff8ece13d5f865a85362a75296ebad07eccf8d3faa9af0f0
• required GLIBC 2.34