v0.2.0

v0.2.0 — a mainnet sync that finishes

The performance release. A fresh mainnet wallet reaches the tip in around
eight and a half minutes: header sync starts from a shipped checkpoint whose
provenance is derived rather than asserted — generated by syncing from
genesis with this code, reproducible by anyone via the same path — with
verify-from-genesis kept as a setting. The header chain learns to start
somewhere other than genesis, and a first real mainnet test taught two
lessons that landed as fixes, including wallet deletion.

Correctness alongside: coinbase outputs wait their hundred confirmations,
P2PKH scriptSig windows index correctly, and silent-payment UTXOs are watched
so compact filters see their spends.

The site becomes source-of-truth pages — the build that regenerated them is
deleted — the custody ladder is published, and the talk becomes a live
walkthrough with a measured nineteen seconds per transaction.