perf(azure): eliminate fleet lists from slot reads - #391

Summary

• replace owned-slot resource-group inventories with exact deterministic Azure object reads
• issue independent exact reads in a bounded parallel batch
• preserve whole-fleet capacity, spend, and conflict inventory at queued admission
• recognize real Azure missing-resource response shapes while failing closed on other errors

Evidence

• production canary for PR perf(azure): scope worker inventory to its slot #390 succeeded and reduced total time from 20m20s to 13m48s
• the canary reviewer identified remaining top-level fleet lists in the owned-slot path
• live read-only exact-slot probe completes in 2.58s with no resource-group list calls
• focused Azure lifecycle, wrapper, pilot, service-scope, and outcome-transport suites pass