Lock the design choices from the 2026-05-19 review against the intervening
2026-05-14 onchain-zaps work:
- Move the module from quartz/.../nip03Timestamp/bitcoin/ to a sibling
quartz/.../bitcoin/ package so the headers explorer, header validator,
peer pool and store can be reused by the future onchain-zap merkle-proof
work without an inverted import path.
- Use androidx.sqlite + BundledSQLiteDriver for HeaderStore, matching the
existing SQLiteEventStore. Schema lives in commonMain via IModule. Drops
the hand-rolled flat-file + sidecar height index.
- Drop the bundled headers blob. Ship a single hardcoded PinnedCheckpoint
constant; first-run sync starts from the checkpoint and pulls forward
over P2P. APK growth: 0 bytes.
- Pre-checkpoint OTS heights fall through to OkHttpBitcoinExplorer via
BitcoinExplorerEndpoint (shared with the onchain-zap EsploraBackend).
Strict-mode users get an explicit error instead of a network call.
- Mark trustless NIP-BC onchain-zap verification as out of scope and
capture it as a follow-up plan (BIP-37 merkleblock or full-block fetch
on top of this stack).
Resolves open questions Q1, Q2 and Q4 from the original plan; Q3 (Quartz
public API vs internal) left open for Phase 0.
Comprehensive design doc for a headers-only Bitcoin P2P client that would
let NIP-03 OTS attestations be verified locally against the proof-of-work
chain instead of a trusted block explorer. Parked pending direction on
NIP-BC onchain-zaps verification, which has overlapping requirements.
Claude