[Epic] Full Node tier: snapshot-free, small-footprint, secure, pure-Go

[Reiers]

Epic: Lantern Full Node tier — snapshot-free, small-footprint, secure, pure-Go

Tracking issue for the Full node tier ("Full node for everyone, runs on a Mac mini"). Sits above Light (~1 GB, done) and PDP/mid = F1 (persistent 2-5 GB, done).

The design (from the 2026-07-01 feasibility work)

A Lantern full node is an F3-anchored full node: it follows and serves the entire chain surface, boots without a snapshot, holds a tunable low-GB working set, and verifies everything pure-Go it can. It does not re-execute the FVM or verify SNARKs natively yet — it trusts the F3 finality layer (the network's own BLS-aggregate 2/3-power BFT) for those. This boot trust is strictly stronger than a single-source 76 GB snapshot import.

Why the two Rust dependencies exist (investigated against lotus master)

Full block validation in Lotus needs filecoin-ffi (Rust) in exactly two places:

1. VerifyWinningPoSt — a Groth16-over-BLS12-381 SNARK verify (#TBD)
2. TipSetState — FVM (WASM) message re-execution (#TBD)

Everything else (VRF, ticket, beacon, block sig, miner-power, win-count) is pure-Go BLS/arithmetic Lantern already has via gnark-crypto.

Staged "kill Rust" roadmap

• Stage A — F3-anchored full node, pure Go, no Rust, no params, Mac-mini-able. Trusts F3 for SNARK+FVM. (child issues below)
• Stage B — pure-Go WinningPoSt verify via gnark + poseidon + small verifying-key fetch. Removes ffi dep Close gossipsub-side sync lag (parent backfill + direct peers) #1. Approved to start.
• Stage C — pure-Go FVM via wazero + full Go hostcall/gas port, vector-matched to ref-fvm. Removes ffi dep Keystore passphrase silently falls back to empty string when LANTERN_PASS is unset #2. The trustless-re-execute dream. Multi-month research.

Child issues

• Full-node tier: pure-Go block-validation pipeline + tunable resident state #90 Full-node tier wiring (pure-Go block-validation pipeline, observe-mode; awaiting calibration soak)
• chain/exchange BlockSync port: snapshot-free full-node boot #91 chain/exchange BlockSync port (snapshot-free tail-fill) — client-only first, headers-only deep tail
• Retention-finality pruning: full node in single-digit GB (not 76) #92 Retention-finality pruning (<100 GB Lotus hotstore -> single-digit GB) — depth driven by Lift FRC-0089 EC finality calculator (lotus chain/ecfinality): observed-data finality without F3 #96
• Wallet import-from-lotus + export/import + installer question (password-protected) #93 Wallet import-from-lotus (CLI shipped; installer question deferred to installer polish)
• Stage B: pure-Go WinningPoSt verify (remove filecoin-ffi dep #1) #88 Stage B: pure-Go WinningPoSt verify — ship behind observe-mode (log agree/disagree, reject nothing until sustained 100% agreement)
• Lift FRC-0089 EC finality calculator (lotus chain/ecfinality): observed-data finality without F3 #96 FRC-0089 EC finality calculator (shipped: chain/ecfinality, dashboard card, Daemon.ECFinality())
• FVM cross-check mode: use the VM bridge as an auditor (state-root divergence alarm) #98 FVM cross-check mode (VM bridge as auditor) — pragmatic precursor to Stage C
• Stage C: pure-Go FVM via wazero (remove filecoin-ffi dep #2) #89 Stage C: pure-Go FVM via wazero (research; parked, do FVM cross-check mode: use the VM bridge as an auditor (state-root divergence alarm) #98 first)

Sibling epic: #100 (running-head trust / eclipse resistance).

Internal design notes: FULL-NODE-VERDICT, FULL-NODE-LOTUS-LIFT, PURE-GO-PROOFS-FVM (kept out of repo).