db_sync: LMDB→SQLite, multi-instance, etcp_api, chatgui integration
- src/db_sync: LMDB replaced with SQLite (separate tables per instance: db_sync_name_id)
TTL index (author, timestamp), WAL mode, per-instance peers/timers
opaque DB_SYNC_INSTANCE* handle, insert callback, select API
new fields: author_signature, delivered_peers, delivery_chain
transport: etcp_api direct P2P (was etcp_router)
- src/db_sync.h: user-oriented API docs, multi-instance lifecycle
- lib/Makefile.am: liblmdb sources removed
- lib/sqlite3.c+h: SQLite amalgamation added
- topo_node: LMDB→SQLite (src/topo_node_sqlite.c moved from chatgui)
- chatgui: real db_sync.c replaces db_sync_stub.c
chat_core: db_sync_insert_signed + dual-write insert callback
utun_node: db_sync_init/destroy replaces chat_sync_init/destroy
CMakeLists: stubs removed, real db_sync.c added
Evgeny