smartcontract: add TopologyInfo account, flex-algo state, and topology processors

[ben-malbeclabs]

RFC-18 flex-algo · PR 1 of 5 · see rfcs/rfc-0018-flex-algo.md
Series: #3497 · #3512 · #3513 · #3514 · #3515

Summary of Changes

• Adds TopologyInfo onchain account (RFC-18 flex-algo) with admin_group_bit, flex_algo_number, and TopologyConstraint; creates AdminGroupBits resource extension singleton for bit allocation
• Adds four new foundation-only instructions (107–110): CreateTopology, DeleteTopology, ClearTopology, BackfillTopology
• Extends Link with link_topologies (Vec) and link_flags (LINK_FLAG_UNICAST_DRAINED); extends Tenant with include_topologies; adds flex_algo_node_segments to Interface V2
• ActivateLink now requires the unicast-default topology account and auto-tags the link into it
• UpdateLink gains foundation-gated link_topologies update and contributor-gated unicast_drained flag

Diff Breakdown

Category	Files	Lines (+/-)	Net
Core logic	22	+1,306 / -38	+1,268
Scaffolding	49	+133 / -3	+130
Tests	27	+4,592 / -74	+4,518

The scaffolding is mechanical struct field additions (link_topologies: vec![], include_topologies: vec![], flex_algo_node_segments: vec![]) across CLI, SDK, activator, and client to keep the workspace compiling. Core logic is concentrated in the new topology processors, state types, and link/activate updates.

Key files (click to expand)

• smartcontract/programs/doublezero-serviceability/src/state/interface.rs — updates Interface V2 (discriminant 1) to include flex_algo_node_segments: Vec<FlexAlgoNodeSegment>; V1 accounts (pre-CYOA format) are left as-is; pre-RFC-18 V2 accounts on mainnet are upgraded in-place by MigrateDeviceInterfaces before this deserialization path is used
• smartcontract/programs/doublezero-serviceability/src/state/topology.rs — new TopologyInfo account: admin_group_bit (u8), flex_algo_number (128+bit), TopologyConstraint (IncludeAny/Exclude)
• smartcontract/programs/doublezero-serviceability/src/processors/topology/ — five new processors: create (allocates AdminGroupBit, validates IdRange 1–127), delete, clear (removes topology from all links), backfill (allocates FlexAlgoNodeSegment on all device interfaces)
• smartcontract/programs/doublezero-serviceability/src/processors/link/update.rs — adds foundation-gated link_topologies update (validates each topology account onchain) and contributor-gated unicast_drained flag (LINK_FLAG_UNICAST_DRAINED bit 0)
• smartcontract/programs/doublezero-serviceability/src/processors/link/activate.rs — requires unicast_default_topology_account as a mandatory account; auto-tags new link into the unicast-default topology on activation
• smartcontract/programs/doublezero-serviceability/src/processors/globalconfig/set.rs — creates AdminGroupBits ResourceExtension PDA on global config initialization
• smartcontract/programs/doublezero-serviceability/src/state/link.rs — adds link_topologies: Vec<Pubkey>, link_flags: u64, and LINK_FLAG_UNICAST_DRAINED = 0x01
• smartcontract/programs/doublezero-serviceability/src/instructions.rs — registers four new instruction variants (CreateTopology=107, DeleteTopology=108, ClearTopology=109, BackfillTopology=110)

Testing Verification

• make rust-lint and make rust-test pass clean on this branch
• topology_test.rs (~2,400 lines) covers all four topology processors: create/delete/clear/backfill, including error paths (duplicate names, out-of-range bits, unauthorized signers, invalid topology accounts), segment allocation, and multi-topology backfill
• Existing link_wan_test.rs, tenant_test.rs, and telemetry tests updated to account for the new mandatory unicast_default_topology_account in ActivateLink

[elitegreg]

Sorry I told you to consolidate InterfaceV3 into InterfaceV2. Claude actually got it right the first time. Interface is not like our other accounts, and therefore doesn't support adding new fields to the end.