AdminGroupBits ResourceExtension

[ben-malbeclabs]

Add persistent bitmap to track allocated admin-group bits. Bits are never reused after deletion. The UNICAST-DRAINED bit (bit 1) MUST be pre-marked in the bitmap at program initialization — this ensures it is never allocated to a user topology.

Milestone: RFC-18: Onchain Foundation
RFC: #3288

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Files affected:

• smartcontract/programs/doublezero-serviceability/src/state/resource_extension.rs
• smartcontract/programs/doublezero-serviceability/src/processors/resource/

Size: Medium

Tests:

• Bitmap exhaustion returns explicit error
• Allocation always returns lowest available bit
• Deallocated bits are not reused
• Bit 1 pre-marked at initialization; first user topology receives bit 0, second receives bit 2

Blockers: None