[P2-E8.5] Phase-1 → Phase-2 migration path

**Context.** A synchronizer running in Phase 1 (dedicated, no economy) must join Phase 2
without a rebuild: registration, fee state, discount, and reporting attach to an existing
synchronizer; bring-up performed in Phase 1 should already be permissioned and carrying
traffic-control parameters so the delta is purely on-ledger.

**Deliverable.** Documented migration: register existing sync → pay fee → flip base rate
per policy → enable reconciliation; Phase-1 bring-up guidance updated so new Phase-1
syncs are Phase-2-ready.

**Acceptance.** LocalNet scenario: sync bootstrapped "Phase-1 style" joins the economy
with no data loss and no re-bootstrap.

**Depends on.** P2-E1.3, P2-E3.1, P2-E5.3, P2-E8.1.

—
Epic: #71 · Plan: [P2-E8-deployment-ops.md](https://github.com/ChainSafe/canton-extending-mainnet/blob/main/docs/planning/phase-2-epics/P2-E8-deployment-ops.md)

Read docs/planning/phase-2-epics/P2-E8-deployment-ops.md and review dependencies P2-E1.3, P2-E3.1, P2-E5.3, and P2-E8.1 first. Map the documented sequence from registering an existing synchronizer through fee payment, base-rate policy, and reconciliation, then update Phase-1 bring-up guidance. Done means the LocalNet Phase-1-style synchronizer joins the economy without data loss or re-bootstrap.

Written by the indexing model from the issue text.