smartcontract,controlplane: add flex-algo link/tenant CLI extensions and migrate command

[ben-malbeclabs]

RFC-18 flex-algo · PR 3 of 5 · see rfcs/rfc-0018-flex-algo.md
Depends on: #3512 (PR 2)
Series: #3497 · #3512 · #3513 · #3514 · #3515

Summary of Changes

• Extends doublezero link get/list/update to display topology assignments (link_topologies) and drain status, and adds --link-topology filter and --unicast-drained flag to link update
• Extends doublezero tenant get/list/update to display included topologies (include_topologies) and adds --include-topologies flag to tenant update
• Adds doublezero-admin migrate flex-algo [--dry-run] command that backfills link topology assignments and VPNv4 loopback flex-algo node segments across all existing devices and links

Diff Breakdown

Category	Files	Lines (+/-)	Net
Core logic	7	+473 / -32	+441
Scaffolding	5	+18 / -2	+16

Mostly core logic — the migrate command alone is 180 lines of backfill and dry-run orchestration.

Key files (click to expand)

• controlplane/doublezero-admin/src/cli/migrate.rs — new: migrate flex-algo command; validates UNICAST-DEFAULT PDA exists, backfills link topologies for all links, backfills flex-algo node segments for all VPNv4 loopback interfaces on all devices; supports --dry-run
• smartcontract/cli/src/link/list.rs — adds --topology <name> filter and displays link_topologies/unicast_drained columns, resolving topology pubkeys to human-readable names
• smartcontract/cli/src/link/get.rs — displays topology assignments and drain status; fetches topology map to resolve pubkeys to names
• smartcontract/cli/src/link/update.rs — adds --link-topology and --unicast-drained flags
• smartcontract/cli/src/tenant/list.rs — displays include_topologies column
• smartcontract/cli/src/tenant/get.rs — displays included topology names
• smartcontract/cli/src/tenant/update.rs — adds --include-topologies flag

Testing Verification

• cargo test -p doublezero_sdk -p doublezero_cli -p doublezero-admin passes
• cargo clippy -- -D warnings clean
• make rust-fmt applied before commit